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Posted to commits@kafka.apache.org by gw...@apache.org on 2015/08/31 21:26:25 UTC

[1/3] kafka git commit: KAFKA-2475: Make Copycat only have a Converter class instead of Serializer, Deserializer, and Converter.

Repository: kafka
Updated Branches:
  refs/heads/trunk 9c936b186 -> 3803e5cb3


http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/tests/kafkatest/tests/copycat_test.py
----------------------------------------------------------------------
diff --git a/tests/kafkatest/tests/copycat_test.py b/tests/kafkatest/tests/copycat_test.py
index 344f7ef..b4adf53 100644
--- a/tests/kafkatest/tests/copycat_test.py
+++ b/tests/kafkatest/tests/copycat_test.py
@@ -15,8 +15,10 @@
 
 from kafkatest.tests.kafka_test import KafkaTest
 from kafkatest.services.copycat import CopycatStandaloneService
+from kafkatest.services.console_consumer import ConsoleConsumer
 from ducktape.utils.util import wait_until
-import hashlib, subprocess
+from ducktape.mark import parametrize
+import hashlib, subprocess, json
 
 class CopycatStandaloneFileTest(KafkaTest):
     """
@@ -30,8 +32,14 @@ class CopycatStandaloneFileTest(KafkaTest):
 
     OFFSETS_FILE = "/mnt/copycat.offsets"
 
-    FIRST_INPUT = "foo\nbar\nbaz\n"
-    SECOND_INPUT = "razz\nma\ntazz\n"
+    TOPIC = "test"
+
+    FIRST_INPUT_LIST = ["foo", "bar", "baz"]
+    FIRST_INPUT = "\n".join(FIRST_INPUT_LIST) + "\n"
+    SECOND_INPUT_LIST = ["razz", "ma", "tazz"]
+    SECOND_INPUT = "\n".join(SECOND_INPUT_LIST) + "\n"
+
+    SCHEMA = { "type": "string", "optional": False }
 
     def __init__(self, test_context):
         super(CopycatStandaloneFileTest, self).__init__(test_context, num_zk=1, num_brokers=1, topics={
@@ -40,8 +48,18 @@ class CopycatStandaloneFileTest(KafkaTest):
 
         self.source = CopycatStandaloneService(test_context, self.kafka, [self.INPUT_FILE, self.OFFSETS_FILE])
         self.sink = CopycatStandaloneService(test_context, self.kafka, [self.OUTPUT_FILE, self.OFFSETS_FILE])
+        self.consumer_validator = ConsoleConsumer(test_context, 1, self.kafka, self.TOPIC, consumer_timeout_ms=1000)
+
+    @parametrize(converter="org.apache.kafka.copycat.json.JsonConverter", schemas=True)
+    @parametrize(converter="org.apache.kafka.copycat.json.JsonConverter", schemas=False)
+    @parametrize(converter="org.apache.kafka.copycat.storage.StringConverter", schemas=None)
+    def test_file_source_and_sink(self, converter="org.apache.kafka.json.JsonConverter", schemas=True):
+        assert converter != None, "converter type must be set"
+        # Template parameters
+        self.key_converter = converter
+        self.value_converter = converter
+        self.schemas = schemas
 
-    def test_file_source_and_sink(self):
         # These need to be set
         self.source.set_configs(self.render("copycat-standalone.properties"), self.render("copycat-file-source.properties"))
         self.sink.set_configs(self.render("copycat-standalone.properties"), self.render("copycat-file-sink.properties"))
@@ -61,6 +79,13 @@ class CopycatStandaloneFileTest(KafkaTest):
         self.source.node.account.ssh("echo -e -n " + repr(self.SECOND_INPUT) + " >> " + self.INPUT_FILE)
         wait_until(lambda: self.validate_output(self.FIRST_INPUT + self.SECOND_INPUT), timeout_sec=60, err_msg="Sink output file never converged to the same state as the input file")
 
+        # Validate the format of the data in the Kafka topic
+        self.consumer_validator.run()
+        expected = json.dumps([line if not self.schemas else { "schema": self.SCHEMA, "payload": line } for line in self.FIRST_INPUT_LIST + self.SECOND_INPUT_LIST])
+        decoder = (json.loads if converter.endswith("JsonConverter") else str)
+        actual = json.dumps([decoder(x) for x in self.consumer_validator.messages_consumed[1]])
+        assert expected == actual, "Expected %s but saw %s in Kafka" % (expected, actual)
+
     def validate_output(self, value):
         try:
             output_hash = list(self.sink.node.account.ssh_capture("md5sum " + self.OUTPUT_FILE))[0].strip().split()[0]

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/tests/kafkatest/tests/templates/copycat-file-sink.properties
----------------------------------------------------------------------
diff --git a/tests/kafkatest/tests/templates/copycat-file-sink.properties b/tests/kafkatest/tests/templates/copycat-file-sink.properties
index c7865a6..77c43c7 100644
--- a/tests/kafkatest/tests/templates/copycat-file-sink.properties
+++ b/tests/kafkatest/tests/templates/copycat-file-sink.properties
@@ -17,4 +17,4 @@ name=local-file-sink
 connector.class=org.apache.kafka.copycat.file.FileStreamSinkConnector
 tasks.max=1
 file={{ OUTPUT_FILE }}
-topics=test
\ No newline at end of file
+topics={{ TOPIC }}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/tests/kafkatest/tests/templates/copycat-file-source.properties
----------------------------------------------------------------------
diff --git a/tests/kafkatest/tests/templates/copycat-file-source.properties b/tests/kafkatest/tests/templates/copycat-file-source.properties
index 8612ed7..68dabc2 100644
--- a/tests/kafkatest/tests/templates/copycat-file-source.properties
+++ b/tests/kafkatest/tests/templates/copycat-file-source.properties
@@ -17,4 +17,4 @@ name=local-file-source
 connector.class=org.apache.kafka.copycat.file.FileStreamSourceConnector
 tasks.max=1
 file={{ INPUT_FILE }}
-topic=test
\ No newline at end of file
+topic={{ TOPIC }}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/tests/kafkatest/tests/templates/copycat-standalone.properties
----------------------------------------------------------------------
diff --git a/tests/kafkatest/tests/templates/copycat-standalone.properties b/tests/kafkatest/tests/templates/copycat-standalone.properties
index 5ffb487..39db6ce 100644
--- a/tests/kafkatest/tests/templates/copycat-standalone.properties
+++ b/tests/kafkatest/tests/templates/copycat-standalone.properties
@@ -15,11 +15,18 @@
 
 bootstrap.servers={{ kafka.bootstrap_servers() }}
 
-key.converter=org.apache.kafka.copycat.json.JsonConverter
-value.converter=org.apache.kafka.copycat.json.JsonConverter
-key.serializer=org.apache.kafka.copycat.json.JsonSerializer
-value.serializer=org.apache.kafka.copycat.json.JsonSerializer
-key.deserializer=org.apache.kafka.copycat.json.JsonDeserializer
-value.deserializer=org.apache.kafka.copycat.json.JsonDeserializer
+key.converter={{ key_converter|default("org.apache.kafka.copycat.json.JsonConverter") }}
+value.converter={{ value_converter|default("org.apache.kafka.copycat.json.JsonConverter") }}
+{% if key_converter is not defined or key_converter.endswith("JsonConverter") %}
+key.converter.schemas.enable={{ schemas|default(True)|string|lower }}
+{% endif %}
+{% if value_converter is not defined or value_converter.endswith("JsonConverter") %}
+value.converter.schemas.enable={{ schemas|default(True)|string|lower }}
+{% endif %}
+
+offset.key.converter=org.apache.kafka.copycat.json.JsonConverter
+offset.value.converter=org.apache.kafka.copycat.json.JsonConverter
+offset.key.converter.schemas.enable=false
+offset.value.converter.schemas.enable=false
 
 offset.storage.file.filename={{ OFFSETS_FILE }}


[3/3] kafka git commit: KAFKA-2475: Make Copycat only have a Converter class instead of Serializer, Deserializer, and Converter.

Posted by gw...@apache.org.
KAFKA-2475: Make Copycat only have a Converter class instead of Serializer, Deserializer, and Converter.

The Converter class now translates directly between byte[] and Copycat's data
API instead of requiring an intermediate runtime type like Avro's GenericRecord
or Jackson's JsonNode.

Author: Ewen Cheslack-Postava <me...@ewencp.org>

Reviewers: Gwen Shapira

Closes #172 from ewencp/kafka-2475-unified-serializer-converter and squashes the following commits:

566c52f [Ewen Cheslack-Postava] Checkstyle fixes
320d0df [Ewen Cheslack-Postava] Restrict offset format.
85797e7 [Ewen Cheslack-Postava] Add StringConverter for using Copycat with raw strings.
698d65c [Ewen Cheslack-Postava] Move and update outdated comment about handing of types for BYTES type in Copycat.
4bed051 [Ewen Cheslack-Postava] KAFKA-2475: Make Copycat only have a Converter class instead of Serializer, Deserializer, and Converter.


Project: http://git-wip-us.apache.org/repos/asf/kafka/repo
Commit: http://git-wip-us.apache.org/repos/asf/kafka/commit/3803e5cb
Tree: http://git-wip-us.apache.org/repos/asf/kafka/tree/3803e5cb
Diff: http://git-wip-us.apache.org/repos/asf/kafka/diff/3803e5cb

Branch: refs/heads/trunk
Commit: 3803e5cb37cb602ff9eab5562ff8db3a2dd79b45
Parents: 9c936b1
Author: Ewen Cheslack-Postava <me...@ewencp.org>
Authored: Mon Aug 31 12:26:16 2015 -0700
Committer: Gwen Shapira <cs...@gmail.com>
Committed: Mon Aug 31 12:26:16 2015 -0700

----------------------------------------------------------------------
 .../kafka/common/config/AbstractConfig.java     |  15 +
 .../kafka/common/config/AbstractConfigTest.java |  13 +
 config/copycat-standalone.properties            |  17 +-
 .../kafka/copycat/data/CopycatSchema.java       |  92 ++++--
 .../org/apache/kafka/copycat/data/Schema.java   |   1 -
 .../kafka/copycat/data/SchemaBuilder.java       |   3 +-
 .../kafka/copycat/source/SourceRecord.java      |  41 +--
 .../apache/kafka/copycat/storage/Converter.java |  23 +-
 .../copycat/storage/OffsetStorageReader.java    |  13 +-
 .../kafka/copycat/storage/StringConverter.java  |  81 ++++++
 .../copycat/storage/StringConverterTest.java    |  83 ++++++
 .../copycat/file/FileStreamSourceTask.java      |  33 ++-
 .../copycat/file/FileStreamSourceTaskTest.java  |  23 +-
 .../kafka/copycat/json/JsonConverter.java       | 281 +++++++++++++------
 .../kafka/copycat/json/JsonDeserializer.java    |  31 +-
 .../kafka/copycat/json/JsonSerializer.java      |  15 -
 .../kafka/copycat/json/JsonConverterTest.java   | 243 ++++++++++++----
 .../apache/kafka/copycat/cli/WorkerConfig.java  |  35 +--
 .../apache/kafka/copycat/runtime/Worker.java    |  72 ++---
 .../kafka/copycat/runtime/WorkerSinkTask.java   |  30 +-
 .../kafka/copycat/runtime/WorkerSourceTask.java |  39 ++-
 .../storage/OffsetStorageReaderImpl.java        |  39 ++-
 .../copycat/storage/OffsetStorageWriter.java    |  37 ++-
 .../kafka/copycat/storage/OffsetUtils.java      |  46 +++
 .../copycat/runtime/WorkerSinkTaskTest.java     |  26 +-
 .../copycat/runtime/WorkerSourceTaskTest.java   |  60 ++--
 .../kafka/copycat/runtime/WorkerTest.java       |  18 +-
 .../storage/OffsetStorageWriterTest.java        |  42 +--
 tests/kafkatest/tests/copycat_test.py           |  33 ++-
 .../templates/copycat-file-sink.properties      |   2 +-
 .../templates/copycat-file-source.properties    |   2 +-
 .../templates/copycat-standalone.properties     |  19 +-
 32 files changed, 991 insertions(+), 517 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/clients/src/main/java/org/apache/kafka/common/config/AbstractConfig.java
----------------------------------------------------------------------
diff --git a/clients/src/main/java/org/apache/kafka/common/config/AbstractConfig.java b/clients/src/main/java/org/apache/kafka/common/config/AbstractConfig.java
index 774701a..12a1927 100644
--- a/clients/src/main/java/org/apache/kafka/common/config/AbstractConfig.java
+++ b/clients/src/main/java/org/apache/kafka/common/config/AbstractConfig.java
@@ -115,6 +115,21 @@ public class AbstractConfig {
         return copy;
     }
 
+    /**
+     * Gets all original settings with the given prefix, stripping the prefix before adding it to the output.
+     *
+     * @param prefix the prefix to use as a filter
+     * @return a Map containing the settings with the prefix
+     */
+    public Map<String, Object> originalsWithPrefix(String prefix) {
+        Map<String, Object> result = new HashMap<String, Object>();
+        for (Map.Entry<String, ?> entry : originals.entrySet()) {
+            if (entry.getKey().startsWith(prefix) && entry.getKey().length() > prefix.length())
+                result.put(entry.getKey().substring(prefix.length()), entry.getValue());
+        }
+        return result;
+    }
+
     public Map<String, ?> values() {
         return new HashMap<String, Object>(values);
     }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/clients/src/test/java/org/apache/kafka/common/config/AbstractConfigTest.java
----------------------------------------------------------------------
diff --git a/clients/src/test/java/org/apache/kafka/common/config/AbstractConfigTest.java b/clients/src/test/java/org/apache/kafka/common/config/AbstractConfigTest.java
index db1b0ee..28064ec 100644
--- a/clients/src/test/java/org/apache/kafka/common/config/AbstractConfigTest.java
+++ b/clients/src/test/java/org/apache/kafka/common/config/AbstractConfigTest.java
@@ -17,10 +17,12 @@ import org.apache.kafka.common.config.ConfigDef.Type;
 import org.apache.kafka.common.metrics.MetricsReporter;
 import org.junit.Test;
 
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 
 import static org.junit.Assert.fail;
+import static org.junit.Assert.assertEquals;
 
 public class AbstractConfigTest {
 
@@ -35,6 +37,17 @@ public class AbstractConfigTest {
         testInvalidInputs("org.apache.kafka.common.metrics.FakeMetricsReporter,");
     }
 
+    @Test
+    public void testOriginalsWithPrefix() {
+        Properties props = new Properties();
+        props.put("foo.bar", "abc");
+        props.put("setting", "def");
+        TestConfig config = new TestConfig(props);
+        Map<String, Object> expected = new HashMap<>();
+        expected.put("bar", "abc");
+        assertEquals(expected, config.originalsWithPrefix("foo."));
+    }
+
     private void testValidInputs(String configValue) {
         Properties props = new Properties();
         props.put(TestConfig.METRIC_REPORTER_CLASSES_CONFIG, configValue);

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/config/copycat-standalone.properties
----------------------------------------------------------------------
diff --git a/config/copycat-standalone.properties b/config/copycat-standalone.properties
index cf3b268..fd264b5 100644
--- a/config/copycat-standalone.properties
+++ b/config/copycat-standalone.properties
@@ -16,12 +16,21 @@
 # These are defaults. This file just demonstrates how to override some settings.
 bootstrap.servers=localhost:9092
 
+# The converters specify the format of data in Kafka and how to translate it into Copycat data. Every Copycat user will
+# need to configure these based on the format they want their data in when loaded from or stored into Kafka
 key.converter=org.apache.kafka.copycat.json.JsonConverter
 value.converter=org.apache.kafka.copycat.json.JsonConverter
-key.serializer=org.apache.kafka.copycat.json.JsonSerializer
-value.serializer=org.apache.kafka.copycat.json.JsonSerializer
-key.deserializer=org.apache.kafka.copycat.json.JsonDeserializer
-value.deserializer=org.apache.kafka.copycat.json.JsonDeserializer
+# Converter-specific settings can be passed in by prefixing the Converter's setting with the converter we want to apply
+# it to
+key.converter.schemas.enable=true
+value.converter.schemas.enable=true
+
+# The offset converter is configurable and must be specified, but most users will always want to use the built-in default.
+# Offset data is never visible outside of Copcyat.
+offset.key.converter=org.apache.kafka.copycat.json.JsonConverter
+offset.value.converter=org.apache.kafka.copycat.json.JsonConverter
+offset.key.converter.schemas.enable=false
+offset.value.converter.schemas.enable=false
 
 offset.storage.file.filename=/tmp/copycat.offsets
 # Flush much faster than normal, which is useful for testing/debugging

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/data/CopycatSchema.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/data/CopycatSchema.java b/copycat/api/src/main/java/org/apache/kafka/copycat/data/CopycatSchema.java
index c823f28..809496a 100644
--- a/copycat/api/src/main/java/org/apache/kafka/copycat/data/CopycatSchema.java
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/data/CopycatSchema.java
@@ -23,20 +23,37 @@ import java.nio.ByteBuffer;
 import java.util.*;
 
 public class CopycatSchema implements Schema {
-    private static final Map<Type, Class<?>> SCHEMA_TYPE_CLASSES = new HashMap<>();
+    /**
+     * Maps Schema.Types to a list of Java classes that can be used to represent them.
+     */
+    private static final Map<Type, List<Class>> SCHEMA_TYPE_CLASSES = new HashMap<>();
+
+    /**
+     * Maps the Java classes to the corresponding Schema.Type.
+     */
+    private static final Map<Class<?>, Type> JAVA_CLASS_SCHEMA_TYPES = new HashMap<>();
+
     static {
-        SCHEMA_TYPE_CLASSES.put(Type.INT8, Byte.class);
-        SCHEMA_TYPE_CLASSES.put(Type.INT16, Short.class);
-        SCHEMA_TYPE_CLASSES.put(Type.INT32, Integer.class);
-        SCHEMA_TYPE_CLASSES.put(Type.INT64, Long.class);
-        SCHEMA_TYPE_CLASSES.put(Type.FLOAT32, Float.class);
-        SCHEMA_TYPE_CLASSES.put(Type.FLOAT64, Double.class);
-        SCHEMA_TYPE_CLASSES.put(Type.BOOLEAN, Boolean.class);
-        SCHEMA_TYPE_CLASSES.put(Type.STRING, String.class);
-        SCHEMA_TYPE_CLASSES.put(Type.ARRAY, List.class);
-        SCHEMA_TYPE_CLASSES.put(Type.MAP, Map.class);
-        SCHEMA_TYPE_CLASSES.put(Type.STRUCT, Struct.class);
-        // Bytes are handled as a special case
+        SCHEMA_TYPE_CLASSES.put(Type.INT8, Arrays.asList((Class) Byte.class));
+        SCHEMA_TYPE_CLASSES.put(Type.INT16, Arrays.asList((Class) Short.class));
+        SCHEMA_TYPE_CLASSES.put(Type.INT32, Arrays.asList((Class) Integer.class));
+        SCHEMA_TYPE_CLASSES.put(Type.INT64, Arrays.asList((Class) Long.class));
+        SCHEMA_TYPE_CLASSES.put(Type.FLOAT32, Arrays.asList((Class) Float.class));
+        SCHEMA_TYPE_CLASSES.put(Type.FLOAT64, Arrays.asList((Class) Double.class));
+        SCHEMA_TYPE_CLASSES.put(Type.BOOLEAN, Arrays.asList((Class) Boolean.class));
+        SCHEMA_TYPE_CLASSES.put(Type.STRING, Arrays.asList((Class) String.class));
+        // Bytes are special and have 2 representations. byte[] causes problems because it doesn't handle equals() and
+        // hashCode() like we want objects to, so we support both byte[] and ByteBuffer. Using plain byte[] can cause
+        // those methods to fail, so ByteBuffers are recommended
+        SCHEMA_TYPE_CLASSES.put(Type.BYTES, Arrays.asList((Class) byte[].class, (Class) ByteBuffer.class));
+        SCHEMA_TYPE_CLASSES.put(Type.ARRAY, Arrays.asList((Class) List.class));
+        SCHEMA_TYPE_CLASSES.put(Type.MAP, Arrays.asList((Class) Map.class));
+        SCHEMA_TYPE_CLASSES.put(Type.STRUCT, Arrays.asList((Class) Struct.class));
+
+        for (Map.Entry<Type, List<Class>> schemaClasses : SCHEMA_TYPE_CLASSES.entrySet()) {
+            for (Class<?> schemaClass : schemaClasses.getValue())
+                JAVA_CLASS_SCHEMA_TYPES.put(schemaClass, schemaClasses.getKey());
+        }
     }
 
     // The type of the field
@@ -158,14 +175,19 @@ public class CopycatSchema implements Schema {
                 return;
         }
 
-        // Special case for bytes. byte[] causes problems because it doesn't handle equals()/hashCode() like we want
-        // objects to, so we support both byte[] and ByteBuffer. Using plain byte[] can cause those methods to fail, so
-        // ByteBuffers are recommended
-        if (schema.type() == Type.BYTES && (value instanceof byte[] || value instanceof ByteBuffer))
-            return;
-        Class<?> expectedClass = SCHEMA_TYPE_CLASSES.get(schema.type());
-        if (expectedClass == null || !expectedClass.isInstance(value))
-                throw new DataException("Invalid value: expected " + expectedClass + " for type " + schema.type() + " but tried to use " + value.getClass());
+        final List<Class> expectedClasses = SCHEMA_TYPE_CLASSES.get(schema.type());
+        if (expectedClasses == null)
+            throw new DataException("Invalid Java object for schema type " + schema.type() + ": " + value.getClass());
+
+        boolean foundMatch = false;
+        for (Class<?> expectedClass : expectedClasses) {
+            if (expectedClass.isInstance(value)) {
+                foundMatch = true;
+                break;
+            }
+        }
+        if (!foundMatch)
+            throw new DataException("Invalid Java object for schema type " + schema.type() + ": " + value.getClass());
 
         switch (schema.type()) {
             case STRUCT:
@@ -232,4 +254,32 @@ public class CopycatSchema implements Schema {
         else
             return "Schema{" + type + "}";
     }
+
+
+    /**
+     * Get the {@link Type} associated with the the given class.
+     *
+     * @param klass the Class to
+     * @return the corresponding type, nor null if there is no matching type
+     */
+    public static Type schemaType(Class<?> klass) {
+        synchronized (JAVA_CLASS_SCHEMA_TYPES) {
+            Type schemaType = JAVA_CLASS_SCHEMA_TYPES.get(klass);
+            if (schemaType != null)
+                return schemaType;
+
+            // Since the lookup only checks the class, we need to also try
+            for (Map.Entry<Class<?>, Type> entry : JAVA_CLASS_SCHEMA_TYPES.entrySet()) {
+                try {
+                    klass.asSubclass(entry.getKey());
+                    // Cache this for subsequent lookups
+                    JAVA_CLASS_SCHEMA_TYPES.put(klass, entry.getValue());
+                    return entry.getValue();
+                } catch (ClassCastException e) {
+                    // Expected, ignore
+                }
+            }
+        }
+        return null;
+    }
 }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/data/Schema.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/data/Schema.java b/copycat/api/src/main/java/org/apache/kafka/copycat/data/Schema.java
index 5ceb57d..4ece21d 100644
--- a/copycat/api/src/main/java/org/apache/kafka/copycat/data/Schema.java
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/data/Schema.java
@@ -92,7 +92,6 @@ public interface Schema {
     Schema OPTIONAL_STRING_SCHEMA = SchemaBuilder.string().optional().build();
     Schema OPTIONAL_BYTES_SCHEMA = SchemaBuilder.bytes().optional().build();
 
-
     /**
      * @return the type of this schema
      */

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/data/SchemaBuilder.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/data/SchemaBuilder.java b/copycat/api/src/main/java/org/apache/kafka/copycat/data/SchemaBuilder.java
index fe9d474..d9c149d 100644
--- a/copycat/api/src/main/java/org/apache/kafka/copycat/data/SchemaBuilder.java
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/data/SchemaBuilder.java
@@ -21,6 +21,7 @@ import org.apache.kafka.copycat.errors.DataException;
 import org.apache.kafka.copycat.errors.SchemaBuilderException;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -346,7 +347,7 @@ public class SchemaBuilder implements Schema {
      * @return the {@link Schema}
      */
     public Schema build() {
-        return new CopycatSchema(type, isOptional(), defaultValue, name, version, doc, fields, keySchema, valueSchema);
+        return new CopycatSchema(type, isOptional(), defaultValue, name, version, doc, fields == null ? null : Collections.unmodifiableList(fields), keySchema, valueSchema);
     }
 
     /**

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/source/SourceRecord.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/source/SourceRecord.java b/copycat/api/src/main/java/org/apache/kafka/copycat/source/SourceRecord.java
index 05286a1..7f54c10 100644
--- a/copycat/api/src/main/java/org/apache/kafka/copycat/source/SourceRecord.java
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/source/SourceRecord.java
@@ -21,6 +21,8 @@ import org.apache.kafka.common.annotation.InterfaceStability;
 import org.apache.kafka.copycat.connector.CopycatRecord;
 import org.apache.kafka.copycat.data.Schema;
 
+import java.util.Map;
+
 /**
  * <p>
  * SourceRecords are generated by SourceTasks and passed to Copycat for storage in
@@ -41,47 +43,32 @@ import org.apache.kafka.copycat.data.Schema;
  */
 @InterfaceStability.Unstable
 public class SourceRecord extends CopycatRecord {
-    private final Schema sourcePartitionSchema;
-    private final Object sourcePartition;
-    private final Schema sourceOffsetSchema;
-    private final Object sourceOffset;
+    private final Map<String, ?> sourcePartition;
+    private final Map<String, ?> sourceOffset;
 
-    public SourceRecord(Schema sourcePartitionSchema, Object sourcePartition,
-                        Schema sourceOffsetSchema, Object sourceOffset,
+    public SourceRecord(Map<String, ?> sourcePartition, Map<String, ?> sourceOffset,
                         String topic, Integer partition, Schema valueSchema, Object value) {
-        this(sourcePartitionSchema, sourcePartition, sourceOffsetSchema, sourceOffset, topic, partition, null, null, valueSchema, value);
+        this(sourcePartition, sourceOffset, topic, partition, null, null, valueSchema, value);
     }
 
-    public SourceRecord(Schema sourcePartitionSchema, Object sourcePartition,
-                        Schema sourceOffsetSchema, Object sourceOffset,
+    public SourceRecord(Map<String, ?> sourcePartition, Map<String, ?> sourceOffset,
                         String topic, Schema valueSchema, Object value) {
-        this(sourcePartitionSchema, sourcePartition, sourceOffsetSchema, sourceOffset, topic, null, null, null, valueSchema, value);
+        this(sourcePartition, sourceOffset, topic, null, null, null, valueSchema, value);
     }
 
-    public SourceRecord(Schema sourcePartitionSchema, Object sourcePartition,
-                        Schema sourceOffsetSchema, Object sourceOffset,
+    public SourceRecord(Map<String, ?> sourcePartition, Map<String, ?> sourceOffset,
                         String topic, Integer partition,
                         Schema keySchema, Object key, Schema valueSchema, Object value) {
         super(topic, partition, keySchema, key, valueSchema, value);
-        this.sourcePartitionSchema = sourcePartitionSchema;
         this.sourcePartition = sourcePartition;
-        this.sourceOffsetSchema = sourceOffsetSchema;
         this.sourceOffset = sourceOffset;
     }
 
-    public Schema sourcePartitionSchema() {
-        return sourcePartitionSchema;
-    }
-
-    public Object sourcePartition() {
+    public Map<String, ?> sourcePartition() {
         return sourcePartition;
     }
 
-    public Schema sourceOffsetSchema() {
-        return sourceOffsetSchema;
-    }
-
-    public Object sourceOffset() {
+    public Map<String, ?> sourceOffset() {
         return sourceOffset;
     }
 
@@ -96,10 +83,6 @@ public class SourceRecord extends CopycatRecord {
 
         SourceRecord that = (SourceRecord) o;
 
-        if (sourcePartitionSchema != null ? !sourcePartitionSchema.equals(that.sourcePartitionSchema) : that.sourcePartitionSchema != null)
-            return false;
-        if (sourceOffsetSchema != null ? !sourceOffsetSchema.equals(that.sourceOffsetSchema) : that.sourceOffsetSchema != null)
-            return false;
         if (sourcePartition != null ? !sourcePartition.equals(that.sourcePartition) : that.sourcePartition != null)
             return false;
         if (sourceOffset != null ? !sourceOffset.equals(that.sourceOffset) : that.sourceOffset != null)
@@ -111,8 +94,6 @@ public class SourceRecord extends CopycatRecord {
     @Override
     public int hashCode() {
         int result = super.hashCode();
-        result = 31 * result + (sourcePartitionSchema != null ? sourcePartitionSchema.hashCode() : 0);
-        result = 31 * result + (sourceOffsetSchema != null ? sourceOffsetSchema.hashCode() : 0);
         result = 31 * result + (sourcePartition != null ? sourcePartition.hashCode() : 0);
         result = 31 * result + (sourceOffset != null ? sourceOffset.hashCode() : 0);
         return result;

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/storage/Converter.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/storage/Converter.java b/copycat/api/src/main/java/org/apache/kafka/copycat/storage/Converter.java
index dd2068d..d51b789 100644
--- a/copycat/api/src/main/java/org/apache/kafka/copycat/storage/Converter.java
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/storage/Converter.java
@@ -21,28 +21,37 @@ import org.apache.kafka.common.annotation.InterfaceStability;
 import org.apache.kafka.copycat.data.Schema;
 import org.apache.kafka.copycat.data.SchemaAndValue;
 
+import java.util.Map;
+
 /**
  * The Converter interface provides support for translating between Copycat's runtime data format
- * and the "native" runtime format used by the serialization layer. This is used to translate
- * two types of data: records and offsets. The (de)serialization is performed by a separate
- * component -- the producer or consumer serializer or deserializer for records or a Copycat
- * serializer or deserializer for offsets.
+ * and byte[]. Internally, this likely includes an intermediate step to the format used by the serialization
+ * layer (e.g. JsonNode, GenericRecord, Message).
  */
 @InterfaceStability.Unstable
-public interface Converter<T> {
+public interface Converter {
+
+    /**
+     * Configure this class.
+     * @param configs configs in key/value pairs
+     * @param isKey whether is for key or value
+     */
+    void configure(Map<String, ?> configs, boolean isKey);
 
     /**
      * Convert a Copycat data object to a native object for serialization.
+     * @param topic the topic associated with the data
      * @param schema the schema for the value
      * @param value the value to convert
      * @return
      */
-    T fromCopycatData(Schema schema, Object value);
+    byte[] fromCopycatData(String topic, Schema schema, Object value);
 
     /**
      * Convert a native object to a Copycat data object.
+     * @param topic the topic associated with the data
      * @param value the value to convert
      * @return an object containing the {@link Schema} and the converted value
      */
-    SchemaAndValue toCopycatData(T value);
+    SchemaAndValue toCopycatData(String topic, byte[] value);
 }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReader.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReader.java b/copycat/api/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReader.java
index b51fbde..95d2c04 100644
--- a/copycat/api/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReader.java
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReader.java
@@ -18,15 +18,20 @@
 package org.apache.kafka.copycat.storage;
 
 import org.apache.kafka.common.annotation.InterfaceStability;
-import org.apache.kafka.copycat.data.SchemaAndValue;
 
 import java.util.Collection;
 import java.util.Map;
 
 /**
+ * <p>
  * OffsetStorageReader provides access to the offset storage used by sources. This can be used by
  * connectors to determine offsets to start consuming data from. This is most commonly used during
  * initialization of a task, but can also be used during runtime, e.g. when reconfiguring a task.
+ * </p>
+ * <p>
+ * Offsets are always defined as Maps of Strings to primitive types, i.e. all types supported by
+ * {@link org.apache.kafka.copycat.data.Schema} other than Array, Map, and Struct.
+ * </p>
  */
 @InterfaceStability.Unstable
 public interface OffsetStorageReader {
@@ -37,12 +42,12 @@ public interface OffsetStorageReader {
      * @param partition object uniquely identifying the partition of data
      * @return object uniquely identifying the offset in the partition of data
      */
-    SchemaAndValue offset(SchemaAndValue partition);
+    <T> Map<String, Object> offset(Map<String, T> partition);
 
     /**
      * <p>
      * Get a set of offsets for the specified partition identifiers. This may be more efficient
-     * than calling {@link #offset(SchemaAndValue)} repeatedly.
+     * than calling {@link #offset(Map)} repeatedly.
      * </p>
      * <p>
      * Note that when errors occur, this method omits the associated data and tries to return as
@@ -56,5 +61,5 @@ public interface OffsetStorageReader {
      * @param partitions set of identifiers for partitions of data
      * @return a map of partition identifiers to decoded offsets
      */
-    Map<SchemaAndValue, SchemaAndValue> offsets(Collection<SchemaAndValue> partitions);
+    <T> Map<Map<String, T>, Map<String, Object>> offsets(Collection<Map<String, T>> partitions);
 }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/main/java/org/apache/kafka/copycat/storage/StringConverter.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/main/java/org/apache/kafka/copycat/storage/StringConverter.java b/copycat/api/src/main/java/org/apache/kafka/copycat/storage/StringConverter.java
new file mode 100644
index 0000000..8d708f8
--- /dev/null
+++ b/copycat/api/src/main/java/org/apache/kafka/copycat/storage/StringConverter.java
@@ -0,0 +1,81 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+package org.apache.kafka.copycat.storage;
+
+import org.apache.kafka.common.errors.SerializationException;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.apache.kafka.copycat.data.Schema;
+import org.apache.kafka.copycat.data.SchemaAndValue;
+import org.apache.kafka.copycat.errors.DataException;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * {@link Converter} implementation that only supports serializing to strings. When converting Copycat data to bytes,
+ * the schema will be ignored and {@link Object#toString()} will always be invoked to convert the data to a String.
+ * When converting from bytes to Copycat format, the converter will only ever return an optional string schema and
+ * a string or null.
+ *
+ * Encoding configuration is identical to {@link StringSerializer} and {@link StringDeserializer}, but for convenience
+ * this class can also be configured to use the same encoding for both encoding and decoding with the converter.encoding
+ * setting.
+ */
+public class StringConverter implements Converter {
+    private final StringSerializer serializer = new StringSerializer();
+    private final StringDeserializer deserializer = new StringDeserializer();
+
+    public StringConverter() {
+    }
+
+    @Override
+    public void configure(Map<String, ?> configs, boolean isKey) {
+        Map<String, Object> serializerConfigs = new HashMap<>();
+        serializerConfigs.putAll(configs);
+        Map<String, Object> deserializerConfigs = new HashMap<>();
+        deserializerConfigs.putAll(configs);
+
+        Object encodingValue = configs.get("converter.encoding");
+        if (encodingValue != null) {
+            serializerConfigs.put("serializer.encoding", encodingValue);
+            deserializerConfigs.put("deserializer.encoding", encodingValue);
+        }
+
+        serializer.configure(serializerConfigs, isKey);
+        deserializer.configure(deserializerConfigs, isKey);
+    }
+
+    @Override
+    public byte[] fromCopycatData(String topic, Schema schema, Object value) {
+        try {
+            return serializer.serialize(topic, value == null ? null : value.toString());
+        } catch (SerializationException e) {
+            throw new DataException("Failed to serialize to a string: ", e);
+        }
+    }
+
+    @Override
+    public SchemaAndValue toCopycatData(String topic, byte[] value) {
+        try {
+            return new SchemaAndValue(Schema.OPTIONAL_STRING_SCHEMA, deserializer.deserialize(topic, value));
+        } catch (SerializationException e) {
+            throw new DataException("Failed to deserialize string: ", e);
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/api/src/test/java/org/apache/kafka/copycat/storage/StringConverterTest.java
----------------------------------------------------------------------
diff --git a/copycat/api/src/test/java/org/apache/kafka/copycat/storage/StringConverterTest.java b/copycat/api/src/test/java/org/apache/kafka/copycat/storage/StringConverterTest.java
new file mode 100644
index 0000000..3ea69c1
--- /dev/null
+++ b/copycat/api/src/test/java/org/apache/kafka/copycat/storage/StringConverterTest.java
@@ -0,0 +1,83 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+package org.apache.kafka.copycat.storage;
+
+import org.apache.kafka.copycat.data.Schema;
+import org.apache.kafka.copycat.data.SchemaAndValue;
+import org.junit.Test;
+
+import java.io.UnsupportedEncodingException;
+import java.util.Collections;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertArrayEquals;
+
+public class StringConverterTest {
+    private static final String TOPIC = "topic";
+    private static final String SAMPLE_STRING = "a string";
+
+    private StringConverter converter = new StringConverter();
+
+    @Test
+    public void testStringToBytes() throws UnsupportedEncodingException {
+        assertArrayEquals(SAMPLE_STRING.getBytes("UTF8"), converter.fromCopycatData(TOPIC, Schema.STRING_SCHEMA, SAMPLE_STRING));
+    }
+
+    @Test
+    public void testNonStringToBytes() throws UnsupportedEncodingException {
+        assertArrayEquals("true".getBytes("UTF8"), converter.fromCopycatData(TOPIC, Schema.BOOLEAN_SCHEMA, true));
+    }
+
+    @Test
+    public void testNullToBytes() {
+        assertEquals(null, converter.fromCopycatData(TOPIC, Schema.OPTIONAL_STRING_SCHEMA, null));
+    }
+
+    @Test
+    public void testToBytesIgnoresSchema() throws UnsupportedEncodingException {
+        assertArrayEquals("true".getBytes("UTF8"), converter.fromCopycatData(TOPIC, null, true));
+    }
+
+    @Test
+    public void testToBytesNonUtf8Encoding() throws UnsupportedEncodingException {
+        converter.configure(Collections.singletonMap("converter.encoding", "UTF-16"), true);
+        assertArrayEquals(SAMPLE_STRING.getBytes("UTF-16"), converter.fromCopycatData(TOPIC, Schema.STRING_SCHEMA, SAMPLE_STRING));
+    }
+
+    @Test
+    public void testBytesToString() {
+        SchemaAndValue data = converter.toCopycatData(TOPIC, SAMPLE_STRING.getBytes());
+        assertEquals(Schema.OPTIONAL_STRING_SCHEMA, data.schema());
+        assertEquals(SAMPLE_STRING, data.value());
+    }
+
+    @Test
+    public void testBytesNullToString() {
+        SchemaAndValue data = converter.toCopycatData(TOPIC, null);
+        assertEquals(Schema.OPTIONAL_STRING_SCHEMA, data.schema());
+        assertEquals(null, data.value());
+    }
+
+    @Test
+    public void testBytesToStringNonUtf8Encoding() throws UnsupportedEncodingException {
+        converter.configure(Collections.singletonMap("converter.encoding", "UTF-16"), true);
+        SchemaAndValue data = converter.toCopycatData(TOPIC, SAMPLE_STRING.getBytes("UTF-16"));
+        assertEquals(Schema.OPTIONAL_STRING_SCHEMA, data.schema());
+        assertEquals(SAMPLE_STRING, data.value());
+    }
+}

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/file/src/main/java/org/apache/kafka/copycat/file/FileStreamSourceTask.java
----------------------------------------------------------------------
diff --git a/copycat/file/src/main/java/org/apache/kafka/copycat/file/FileStreamSourceTask.java b/copycat/file/src/main/java/org/apache/kafka/copycat/file/FileStreamSourceTask.java
index a841386..91292e9 100644
--- a/copycat/file/src/main/java/org/apache/kafka/copycat/file/FileStreamSourceTask.java
+++ b/copycat/file/src/main/java/org/apache/kafka/copycat/file/FileStreamSourceTask.java
@@ -18,7 +18,6 @@
 package org.apache.kafka.copycat.file;
 
 import org.apache.kafka.copycat.data.Schema;
-import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.errors.CopycatException;
 import org.apache.kafka.copycat.source.SourceRecord;
 import org.apache.kafka.copycat.source.SourceTask;
@@ -26,17 +25,15 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.*;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Properties;
+import java.util.*;
 
 /**
  * FileStreamSourceTask reads from stdin or a file.
  */
 public class FileStreamSourceTask extends SourceTask {
     private static final Logger log = LoggerFactory.getLogger(FileStreamSourceTask.class);
-    private static final Schema OFFSET_KEY_SCHEMA = Schema.STRING_SCHEMA;
-    private static final Schema OFFSET_VALUE_SCHEMA = Schema.OPTIONAL_INT64_SCHEMA;
+    public static final String FILENAME_FIELD = "filename";
+    public  static final String POSITION_FIELD = "position";
     private static final Schema VALUE_SCHEMA = Schema.STRING_SCHEMA;
 
     private String filename;
@@ -66,14 +63,14 @@ public class FileStreamSourceTask extends SourceTask {
         if (stream == null) {
             try {
                 stream = new FileInputStream(filename);
-                SchemaAndValue offsetWithSchema = context.offsetStorageReader().offset(new SchemaAndValue(OFFSET_KEY_SCHEMA, filename));
-                if (offsetWithSchema != null) {
-                    if (!offsetWithSchema.schema().equals(OFFSET_VALUE_SCHEMA))
-                        throw new CopycatException("Unexpected offset schema.");
-                    Long lastRecordedOffset = (Long) offsetWithSchema.value();
+                Map<String, Object> offset = context.offsetStorageReader().offset(Collections.singletonMap(FILENAME_FIELD, filename));
+                if (offset != null) {
+                    Object lastRecordedOffset = offset.get(POSITION_FIELD);
+                    if (lastRecordedOffset != null && !(lastRecordedOffset instanceof Long))
+                        throw new CopycatException("Offset position is the incorrect type");
                     if (lastRecordedOffset != null) {
                         log.debug("Found previous offset, trying to skip to file offset {}", lastRecordedOffset);
-                        long skipLeft = lastRecordedOffset;
+                        long skipLeft = (Long) lastRecordedOffset;
                         while (skipLeft > 0) {
                             try {
                                 long skipped = stream.skip(skipLeft);
@@ -85,7 +82,7 @@ public class FileStreamSourceTask extends SourceTask {
                         }
                         log.debug("Skipped to offset {}", lastRecordedOffset);
                     }
-                    streamOffset = (lastRecordedOffset != null) ? lastRecordedOffset : 0L;
+                    streamOffset = (lastRecordedOffset != null) ? (Long) lastRecordedOffset : 0L;
                 } else {
                     streamOffset = 0L;
                 }
@@ -130,7 +127,7 @@ public class FileStreamSourceTask extends SourceTask {
                         if (line != null) {
                             if (records == null)
                                 records = new ArrayList<>();
-                            records.add(new SourceRecord(OFFSET_KEY_SCHEMA, filename, OFFSET_VALUE_SCHEMA, streamOffset, topic, VALUE_SCHEMA, line));
+                            records.add(new SourceRecord(offsetKey(filename), offsetValue(streamOffset), topic, VALUE_SCHEMA, line));
                         }
                         new ArrayList<SourceRecord>();
                     } while (line != null);
@@ -193,4 +190,12 @@ public class FileStreamSourceTask extends SourceTask {
             this.notify();
         }
     }
+
+    private Map<String, String> offsetKey(String filename) {
+        return Collections.singletonMap(FILENAME_FIELD, filename);
+    }
+
+    private Map<String, Long> offsetValue(Long pos) {
+        return Collections.singletonMap(POSITION_FIELD, pos);
+    }
 }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/file/src/test/java/org/apache/kafka/copycat/file/FileStreamSourceTaskTest.java
----------------------------------------------------------------------
diff --git a/copycat/file/src/test/java/org/apache/kafka/copycat/file/FileStreamSourceTaskTest.java b/copycat/file/src/test/java/org/apache/kafka/copycat/file/FileStreamSourceTaskTest.java
index ab89b6a..d2781c9 100644
--- a/copycat/file/src/test/java/org/apache/kafka/copycat/file/FileStreamSourceTaskTest.java
+++ b/copycat/file/src/test/java/org/apache/kafka/copycat/file/FileStreamSourceTaskTest.java
@@ -17,7 +17,6 @@
 
 package org.apache.kafka.copycat.file;
 
-import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.errors.CopycatException;
 import org.apache.kafka.copycat.source.SourceRecord;
 import org.apache.kafka.copycat.source.SourceTaskContext;
@@ -31,7 +30,9 @@ import org.powermock.api.easymock.PowerMock;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import static org.junit.Assert.assertEquals;
@@ -89,7 +90,8 @@ public class FileStreamSourceTaskTest {
         assertEquals(1, records.size());
         assertEquals(TOPIC, records.get(0).topic());
         assertEquals("partial line finished", records.get(0).value());
-        assertEquals(22L, records.get(0).sourceOffset());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.FILENAME_FIELD, tempFile.getAbsolutePath()), records.get(0).sourcePartition());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.POSITION_FIELD, 22L), records.get(0).sourceOffset());
         assertEquals(null, task.poll());
 
         // Different line endings, and make sure the final \r doesn't result in a line until we can
@@ -99,20 +101,25 @@ public class FileStreamSourceTaskTest {
         records = task.poll();
         assertEquals(4, records.size());
         assertEquals("line1", records.get(0).value());
-        assertEquals(28L, records.get(0).sourceOffset());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.FILENAME_FIELD, tempFile.getAbsolutePath()), records.get(0).sourcePartition());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.POSITION_FIELD, 28L), records.get(0).sourceOffset());
         assertEquals("line2", records.get(1).value());
-        assertEquals(35L, records.get(1).sourceOffset());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.FILENAME_FIELD, tempFile.getAbsolutePath()), records.get(1).sourcePartition());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.POSITION_FIELD, 35L), records.get(1).sourceOffset());
         assertEquals("line3", records.get(2).value());
-        assertEquals(41L, records.get(2).sourceOffset());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.FILENAME_FIELD, tempFile.getAbsolutePath()), records.get(2).sourcePartition());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.POSITION_FIELD, 41L), records.get(2).sourceOffset());
         assertEquals("line4", records.get(3).value());
-        assertEquals(47L, records.get(3).sourceOffset());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.FILENAME_FIELD, tempFile.getAbsolutePath()), records.get(3).sourcePartition());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.POSITION_FIELD, 47L), records.get(3).sourceOffset());
 
         os.write("subsequent text".getBytes());
         os.flush();
         records = task.poll();
         assertEquals(1, records.size());
         assertEquals("", records.get(0).value());
-        assertEquals(48L, records.get(0).sourceOffset());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.FILENAME_FIELD, tempFile.getAbsolutePath()), records.get(0).sourcePartition());
+        assertEquals(Collections.singletonMap(FileStreamSourceTask.POSITION_FIELD, 48L), records.get(0).sourceOffset());
 
         task.stop();
     }
@@ -135,6 +142,6 @@ public class FileStreamSourceTaskTest {
 
 
     private void expectOffsetLookupReturnNone() {
-        EasyMock.expect(offsetStorageReader.offset(EasyMock.anyObject(SchemaAndValue.class))).andReturn(null);
+        EasyMock.expect(offsetStorageReader.offset(EasyMock.anyObject(Map.class))).andReturn(null);
     }
 }
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonConverter.java
----------------------------------------------------------------------
diff --git a/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonConverter.java b/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonConverter.java
index 67df11d..1841640 100644
--- a/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonConverter.java
+++ b/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonConverter.java
@@ -21,6 +21,7 @@ import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ArrayNode;
 import com.fasterxml.jackson.databind.node.JsonNodeFactory;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.apache.kafka.common.errors.SerializationException;
 import org.apache.kafka.copycat.data.*;
 import org.apache.kafka.copycat.errors.DataException;
 import org.apache.kafka.copycat.storage.Converter;
@@ -32,7 +33,9 @@ import java.util.*;
 /**
  * Implementation of Converter that uses JSON to store schemas and objects.
  */
-public class JsonConverter implements Converter<JsonNode> {
+public class JsonConverter implements Converter {
+    private static final String SCHEMAS_ENABLE_CONFIG = "schemas.enable";
+    private static final boolean SCHEMAS_ENABLE_DEFAULT = true;
 
     private static final HashMap<Schema.Type, JsonToCopycatTypeConverter> TO_COPYCAT_CONVERTERS = new HashMap<>();
 
@@ -117,9 +120,7 @@ public class JsonConverter implements Converter<JsonNode> {
             public Object convert(Schema schema, JsonNode value) {
                 if (value.isNull()) return checkOptionalAndDefault(schema);
 
-                Schema elemSchema = schema.valueSchema();
-                if (elemSchema == null)
-                    throw new DataException("Array schema did not specify the element type");
+                Schema elemSchema = schema == null ? null : schema.valueSchema();
                 ArrayList<Object> result = new ArrayList<>();
                 for (JsonNode elem : value) {
                     result.add(convertToCopycat(elemSchema, elem));
@@ -132,13 +133,14 @@ public class JsonConverter implements Converter<JsonNode> {
             public Object convert(Schema schema, JsonNode value) {
                 if (value.isNull()) return checkOptionalAndDefault(schema);
 
-                Schema keySchema = schema.keySchema();
-                Schema valueSchema = schema.valueSchema();
+                Schema keySchema = schema == null ? null : schema.keySchema();
+                Schema valueSchema = schema == null ? null : schema.valueSchema();
 
                 // If the map uses strings for keys, it should be encoded in the natural JSON format. If it uses other
-                // primitive types or a complex type as a key, it will be encoded as a list of pairs
+                // primitive types or a complex type as a key, it will be encoded as a list of pairs. If we don't have a
+                // schema, we default to encoding in a Map.
                 Map<Object, Object> result = new HashMap<>();
-                if (keySchema.type() == Schema.Type.STRING) {
+                if (schema == null || keySchema.type() == Schema.Type.STRING) {
                     if (!value.isObject())
                         throw new DataException("Map's with string fields should be encoded as JSON objects, but found " + value.getNodeType());
                     Iterator<Map.Entry<String, JsonNode>> fieldIt = value.fields();
@@ -182,24 +184,73 @@ public class JsonConverter implements Converter<JsonNode> {
             }
         });
 
+
+    }
+
+    private boolean enableSchemas = SCHEMAS_ENABLE_DEFAULT;
+
+    private final JsonSerializer serializer = new JsonSerializer();
+    private final JsonDeserializer deserializer = new JsonDeserializer();
+
+    @Override
+    public void configure(Map<String, ?> configs, boolean isKey) {
+        Object enableConfigsVal = configs.get(SCHEMAS_ENABLE_CONFIG);
+        if (enableConfigsVal != null)
+            enableSchemas = enableConfigsVal.toString().equals("true");
+
+        serializer.configure(configs, isKey);
+        deserializer.configure(configs, isKey);
     }
 
     @Override
-    public JsonNode fromCopycatData(Schema schema, Object value) {
-        return convertToJsonWithSchemaEnvelope(schema, value);
+    public byte[] fromCopycatData(String topic, Schema schema, Object value) {
+        JsonNode jsonValue = enableSchemas ? convertToJsonWithEnvelope(schema, value) : convertToJsonWithoutEnvelope(schema, value);
+        try {
+            return serializer.serialize(topic, jsonValue);
+        } catch (SerializationException e) {
+            throw new DataException("Converting Copycat data to byte[] failed due to serialization error: ", e);
+        }
     }
 
     @Override
-    public SchemaAndValue toCopycatData(JsonNode value) {
-        if (!value.isObject() || value.size() != 2 || !value.has(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME) || !value.has(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME))
-            throw new DataException("JSON value converted to Copycat must be in envelope containing schema");
+    public SchemaAndValue toCopycatData(String topic, byte[] value) {
+        JsonNode jsonValue;
+        try {
+            jsonValue = deserializer.deserialize(topic, value);
+        } catch (SerializationException e) {
+            throw new DataException("Converting byte[] to Copycat data failed due to serialization error: ", e);
+        }
 
-        Schema schema = asCopycatSchema(value.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
-        return new SchemaAndValue(schema, convertToCopycat(schema, value.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME)));
+        if (enableSchemas && (jsonValue == null || !jsonValue.isObject() || jsonValue.size() != 2 || !jsonValue.has("schema") || !jsonValue.has("payload")))
+            throw new DataException("JsonDeserializer with schemas.enable requires \"schema\" and \"payload\" fields and may not contain additional fields");
+
+        // The deserialized data should either be an envelope object containing the schema and the payload or the schema
+        // was stripped during serialization and we need to fill in an all-encompassing schema.
+        if (!enableSchemas) {
+            ObjectNode envelope = JsonNodeFactory.instance.objectNode();
+            envelope.set("schema", null);
+            envelope.set("payload", jsonValue);
+            jsonValue = envelope;
+        }
+
+        return jsonToCopycat(jsonValue);
     }
 
+    private SchemaAndValue jsonToCopycat(JsonNode jsonValue) {
+        if (jsonValue == null)
+            return SchemaAndValue.NULL;
+
+        if (!jsonValue.isObject() || jsonValue.size() != 2 || !jsonValue.has(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME) || !jsonValue.has(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME))
+            throw new DataException("JSON value converted to Copycat must be in envelope containing schema");
+
+        Schema schema = asCopycatSchema(jsonValue.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
+        return new SchemaAndValue(schema, convertToCopycat(schema, jsonValue.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME)));
+    }
 
     private static ObjectNode asJsonSchema(Schema schema) {
+        if (schema == null)
+            return null;
+
         final ObjectNode jsonSchema;
         switch (schema.type()) {
             case BOOLEAN:
@@ -369,16 +420,22 @@ public class JsonConverter implements Converter<JsonNode> {
      * @param value the value
      * @return JsonNode-encoded version
      */
-    private static JsonNode convertToJsonWithSchemaEnvelope(Schema schema, Object value) {
+    private static JsonNode convertToJsonWithEnvelope(Schema schema, Object value) {
         return new JsonSchema.Envelope(asJsonSchema(schema), convertToJson(schema, value)).toJsonNode();
     }
 
+    private static JsonNode convertToJsonWithoutEnvelope(Schema schema, Object value) {
+        return convertToJson(schema, value);
+    }
+
     /**
      * Convert this object, in the org.apache.kafka.copycat.data format, into a JSON object, returning both the schema
      * and the converted object.
      */
     private static JsonNode convertToJson(Schema schema, Object value) {
         if (value == null) {
+            if (schema == null) // Any schema is valid and we don't have a default, so treat this as an optional schema
+                return null;
             if (schema.defaultValue() != null)
                 return convertToJson(schema, schema.defaultValue());
             if (schema.isOptional())
@@ -386,85 +443,141 @@ public class JsonConverter implements Converter<JsonNode> {
             throw new DataException("Conversion error: null value for field that is required and has no default value");
         }
 
-        switch (schema.type()) {
-            case INT8:
-                return JsonNodeFactory.instance.numberNode((Byte) value);
-            case INT16:
-                return JsonNodeFactory.instance.numberNode((Short) value);
-            case INT32:
-                return JsonNodeFactory.instance.numberNode((Integer) value);
-            case INT64:
-                return JsonNodeFactory.instance.numberNode((Long) value);
-            case FLOAT32:
-                return JsonNodeFactory.instance.numberNode((Float) value);
-            case FLOAT64:
-                return JsonNodeFactory.instance.numberNode((Double) value);
-            case BOOLEAN:
-                return JsonNodeFactory.instance.booleanNode((Boolean) value);
-            case STRING:
-                CharSequence charSeq = (CharSequence) value;
-                return JsonNodeFactory.instance.textNode(charSeq.toString());
-            case BYTES:
-                if (value instanceof byte[])
-                    return JsonNodeFactory.instance.binaryNode((byte[]) value);
-                else if (value instanceof ByteBuffer)
-                    return JsonNodeFactory.instance.binaryNode(((ByteBuffer) value).array());
-                else
-                    throw new DataException("Invalid type for bytes type: " + value.getClass());
-            case ARRAY: {
-                if (!(value instanceof Collection))
-                    throw new DataException("Invalid type for array type: " + value.getClass());
-                Collection collection = (Collection) value;
-                ArrayNode list = JsonNodeFactory.instance.arrayNode();
-                for (Object elem : collection) {
-                    JsonNode fieldValue = convertToJson(schema.valueSchema(), elem);
-                    list.add(fieldValue);
-                }
-                return list;
+        try {
+            final Schema.Type schemaType;
+            if (schema == null) {
+                schemaType = CopycatSchema.schemaType(value.getClass());
+                if (schemaType == null)
+                    throw new DataException("Java class " + value.getClass() + " does not have corresponding schema type.");
+            } else {
+                schemaType = schema.type();
             }
-            case MAP: {
-                if (!(value instanceof Map))
-                    throw new DataException("Invalid type for array type: " + value.getClass());
-                Map<?, ?> map = (Map<?, ?>) value;
-                // If true, using string keys and JSON object; if false, using non-string keys and Array-encoding
-                boolean objectMode = schema.keySchema().type() == Schema.Type.STRING;
-                ObjectNode obj = null;
-                ArrayNode list = null;
-                if (objectMode)
-                    obj = JsonNodeFactory.instance.objectNode();
-                else
-                    list = JsonNodeFactory.instance.arrayNode();
-                for (Map.Entry<?, ?> entry : map.entrySet()) {
-                    JsonNode mapKey = convertToJson(schema.keySchema(), entry.getKey());
-                    JsonNode mapValue = convertToJson(schema.valueSchema(), entry.getValue());
-
+            switch (schemaType) {
+                case INT8:
+                    return JsonNodeFactory.instance.numberNode((Byte) value);
+                case INT16:
+                    return JsonNodeFactory.instance.numberNode((Short) value);
+                case INT32:
+                    return JsonNodeFactory.instance.numberNode((Integer) value);
+                case INT64:
+                    return JsonNodeFactory.instance.numberNode((Long) value);
+                case FLOAT32:
+                    return JsonNodeFactory.instance.numberNode((Float) value);
+                case FLOAT64:
+                    return JsonNodeFactory.instance.numberNode((Double) value);
+                case BOOLEAN:
+                    return JsonNodeFactory.instance.booleanNode((Boolean) value);
+                case STRING:
+                    CharSequence charSeq = (CharSequence) value;
+                    return JsonNodeFactory.instance.textNode(charSeq.toString());
+                case BYTES:
+                    if (value instanceof byte[])
+                        return JsonNodeFactory.instance.binaryNode((byte[]) value);
+                    else if (value instanceof ByteBuffer)
+                        return JsonNodeFactory.instance.binaryNode(((ByteBuffer) value).array());
+                    else
+                        throw new DataException("Invalid type for bytes type: " + value.getClass());
+                case ARRAY: {
+                    Collection collection = (Collection) value;
+                    ArrayNode list = JsonNodeFactory.instance.arrayNode();
+                    for (Object elem : collection) {
+                        Schema valueSchema = schema == null ? null : schema.valueSchema();
+                        JsonNode fieldValue = convertToJson(valueSchema, elem);
+                        list.add(fieldValue);
+                    }
+                    return list;
+                }
+                case MAP: {
+                    Map<?, ?> map = (Map<?, ?>) value;
+                    // If true, using string keys and JSON object; if false, using non-string keys and Array-encoding
+                    boolean objectMode;
+                    if (schema == null) {
+                        objectMode = true;
+                        for (Map.Entry<?, ?> entry : map.entrySet()) {
+                            if (!(entry.getKey() instanceof String)) {
+                                objectMode = false;
+                                break;
+                            }
+                        }
+                    } else {
+                        objectMode = schema.keySchema().type() == Schema.Type.STRING;
+                    }
+                    ObjectNode obj = null;
+                    ArrayNode list = null;
                     if (objectMode)
-                        obj.set(mapKey.asText(), mapValue);
+                        obj = JsonNodeFactory.instance.objectNode();
                     else
-                        list.add(JsonNodeFactory.instance.arrayNode().add(mapKey).add(mapValue));
+                        list = JsonNodeFactory.instance.arrayNode();
+                    for (Map.Entry<?, ?> entry : map.entrySet()) {
+                        Schema keySchema = schema == null ? null : schema.keySchema();
+                        Schema valueSchema = schema == null ? null : schema.valueSchema();
+                        JsonNode mapKey = convertToJson(keySchema, entry.getKey());
+                        JsonNode mapValue = convertToJson(valueSchema, entry.getValue());
+
+                        if (objectMode)
+                            obj.set(mapKey.asText(), mapValue);
+                        else
+                            list.add(JsonNodeFactory.instance.arrayNode().add(mapKey).add(mapValue));
+                    }
+                    return objectMode ? obj : list;
                 }
-                return objectMode ? obj : list;
-            }
-            case STRUCT: {
-                if (!(value instanceof Struct))
-                    throw new DataException("Invalid type for struct type: " + value.getClass());
-                Struct struct = (Struct) value;
-                if (struct.schema() != schema)
-                    throw new DataException("Mismatching schema.");
-                ObjectNode obj = JsonNodeFactory.instance.objectNode();
-                for (Field field : schema.fields()) {
-                    obj.set(field.name(), convertToJson(field.schema(), struct.get(field)));
+                case STRUCT: {
+                    Struct struct = (Struct) value;
+                    if (struct.schema() != schema)
+                        throw new DataException("Mismatching schema.");
+                    ObjectNode obj = JsonNodeFactory.instance.objectNode();
+                    for (Field field : schema.fields()) {
+                        obj.set(field.name(), convertToJson(field.schema(), struct.get(field)));
+                    }
+                    return obj;
                 }
-                return obj;
             }
-        }
 
-        throw new DataException("Couldn't convert " + value + " to JSON.");
+            throw new DataException("Couldn't convert " + value + " to JSON.");
+        } catch (ClassCastException e) {
+            throw new DataException("Invalid type for " + schema.type() + ": " + value.getClass());
+        }
     }
 
 
     private static Object convertToCopycat(Schema schema, JsonNode jsonValue) {
-        JsonToCopycatTypeConverter typeConverter = TO_COPYCAT_CONVERTERS.get(schema.type());
+        JsonToCopycatTypeConverter typeConverter;
+        final Schema.Type schemaType;
+        if (schema != null) {
+            schemaType = schema.type();
+        } else {
+            switch (jsonValue.getNodeType()) {
+                case NULL:
+                    // Special case. With no schema
+                    return null;
+                case BOOLEAN:
+                    schemaType = Schema.Type.BOOLEAN;
+                    break;
+                case NUMBER:
+                    if (jsonValue.isIntegralNumber())
+                        schemaType = Schema.Type.INT64;
+                    else
+                        schemaType = Schema.Type.FLOAT64;
+                    break;
+                case ARRAY:
+                    schemaType = Schema.Type.ARRAY;
+                    break;
+                case OBJECT:
+                    schemaType = Schema.Type.MAP;
+                    break;
+                case STRING:
+                    schemaType = Schema.Type.STRING;
+                    break;
+
+                case BINARY:
+                case MISSING:
+                case POJO:
+                default:
+                    schemaType = null;
+                    break;
+            }
+        }
+        typeConverter = TO_COPYCAT_CONVERTERS.get(schemaType);
         if (typeConverter == null)
             throw new DataException("Unknown schema type: " + schema.type());
 

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonDeserializer.java
----------------------------------------------------------------------
diff --git a/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonDeserializer.java b/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonDeserializer.java
index 29c7bac..1661754 100644
--- a/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonDeserializer.java
+++ b/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonDeserializer.java
@@ -18,9 +18,6 @@ package org.apache.kafka.copycat.json;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.node.ArrayNode;
-import com.fasterxml.jackson.databind.node.JsonNodeFactory;
-import com.fasterxml.jackson.databind.node.ObjectNode;
 import org.apache.kafka.common.errors.SerializationException;
 import org.apache.kafka.common.serialization.Deserializer;
 
@@ -31,22 +28,6 @@ import java.util.Map;
  * structured data without having associated Java classes. This deserializer also supports Copycat schemas.
  */
 public class JsonDeserializer implements Deserializer<JsonNode> {
-    private static final ObjectNode CATCH_ALL_OBJECT_SCHEMA = JsonNodeFactory.instance.objectNode();
-    private static final ObjectNode CATCH_ALL_ARRAY_SCHEMA = JsonNodeFactory.instance.objectNode();
-    private static final ArrayNode ALL_SCHEMAS_LIST = JsonNodeFactory.instance.arrayNode();
-    private static final ObjectNode CATCH_ALL_SCHEMA = JsonNodeFactory.instance.objectNode();
-    static {
-        CATCH_ALL_OBJECT_SCHEMA.put("type", "object")
-                .putArray("field").add(JsonNodeFactory.instance.objectNode().put("*", "all"));
-
-        CATCH_ALL_ARRAY_SCHEMA.put("type", "array").put("items", "all");
-
-        ALL_SCHEMAS_LIST.add("boolean").add("int").add("long").add("float").add("double").add("bytes").add("string")
-                .add(CATCH_ALL_ARRAY_SCHEMA).add(CATCH_ALL_OBJECT_SCHEMA);
-
-        CATCH_ALL_SCHEMA.put("name", "all").set("type", ALL_SCHEMAS_LIST);
-    }
-
     private ObjectMapper objectMapper = new ObjectMapper();
 
     /**
@@ -61,6 +42,9 @@ public class JsonDeserializer implements Deserializer<JsonNode> {
 
     @Override
     public JsonNode deserialize(String topic, byte[] bytes) {
+        if (bytes == null)
+            return null;
+
         JsonNode data;
         try {
             data = objectMapper.readTree(bytes);
@@ -68,15 +52,6 @@ public class JsonDeserializer implements Deserializer<JsonNode> {
             throw new SerializationException(e);
         }
 
-        // The deserialized data should either be an envelope object containing the schema and the payload or the schema
-        // was stripped during serialization and we need to fill in an all-encompassing schema.
-        if (!data.isObject() || data.size() != 2 || !data.has("schema") || !data.has("payload")) {
-            ObjectNode envelope = JsonNodeFactory.instance.objectNode();
-            envelope.set("schema", CATCH_ALL_SCHEMA);
-            envelope.set("payload", data);
-            data = envelope;
-        }
-
         return data;
     }
 

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonSerializer.java
----------------------------------------------------------------------
diff --git a/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonSerializer.java b/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonSerializer.java
index 80df6be..129d14b 100644
--- a/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonSerializer.java
+++ b/copycat/json/src/main/java/org/apache/kafka/copycat/json/JsonSerializer.java
@@ -28,12 +28,7 @@ import java.util.Map;
  * structured data without corresponding Java classes. This serializer also supports Copycat schemas.
  */
 public class JsonSerializer implements Serializer<JsonNode> {
-
-    private static final String SCHEMAS_ENABLE_CONFIG = "schemas.enable";
-    private static final boolean SCHEMAS_ENABLE_DEFAULT = true;
-
     private final ObjectMapper objectMapper = new ObjectMapper();
-    private boolean enableSchemas = SCHEMAS_ENABLE_DEFAULT;
 
     /**
      * Default constructor needed by Kafka
@@ -44,9 +39,6 @@ public class JsonSerializer implements Serializer<JsonNode> {
 
     @Override
     public void configure(Map<String, ?> config, boolean isKey) {
-        Object enableConfigsVal = config.get(SCHEMAS_ENABLE_CONFIG);
-        if (enableConfigsVal != null)
-            enableSchemas = enableConfigsVal.toString().equals("true");
     }
 
     @Override
@@ -54,14 +46,7 @@ public class JsonSerializer implements Serializer<JsonNode> {
         if (data == null)
             return null;
 
-        // This serializer works for Copycat data that requires a schema to be included, so we expect it to have a
-        // specific format: { "schema": {...}, "payload": ... }.
-        if (!data.isObject() || data.size() != 2 || !data.has("schema") || !data.has("payload"))
-            throw new SerializationException("JsonSerializer requires \"schema\" and \"payload\" fields and may not contain additional fields");
-
         try {
-            if (!enableSchemas)
-                data = data.get("payload");
             return objectMapper.writeValueAsBytes(data);
         } catch (Exception e) {
             throw new SerializationException("Error serializing JSON message", e);


[2/3] kafka git commit: KAFKA-2475: Make Copycat only have a Converter class instead of Serializer, Deserializer, and Converter.

Posted by gw...@apache.org.
http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/json/src/test/java/org/apache/kafka/copycat/json/JsonConverterTest.java
----------------------------------------------------------------------
diff --git a/copycat/json/src/test/java/org/apache/kafka/copycat/json/JsonConverterTest.java b/copycat/json/src/test/java/org/apache/kafka/copycat/json/JsonConverterTest.java
index ab4a86e..214f9ce 100644
--- a/copycat/json/src/test/java/org/apache/kafka/copycat/json/JsonConverterTest.java
+++ b/copycat/json/src/test/java/org/apache/kafka/copycat/json/JsonConverterTest.java
@@ -19,19 +19,19 @@ package org.apache.kafka.copycat.json;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
 import com.fasterxml.jackson.databind.node.JsonNodeFactory;
 import org.apache.kafka.copycat.data.Schema;
 import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.data.SchemaBuilder;
 import org.apache.kafka.copycat.data.Struct;
+import org.apache.kafka.copycat.errors.DataException;
 import org.junit.Test;
 
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.Map;
+import java.util.*;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
@@ -39,6 +39,7 @@ import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 public class JsonConverterTest {
+    private static final String TOPIC = "topic";
 
     ObjectMapper objectMapper = new ObjectMapper();
     JsonConverter converter = new JsonConverter();
@@ -48,51 +49,51 @@ public class JsonConverterTest {
     @Test
     public void testCopycatSchemaMetadataTranslation() {
         // this validates the non-type fields are translated and handled properly
-        assertEquals(new SchemaAndValue(Schema.BOOLEAN_SCHEMA, true), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"boolean\" }, \"payload\": true }")));
-        assertEquals(new SchemaAndValue(Schema.OPTIONAL_BOOLEAN_SCHEMA, null), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"boolean\", \"optional\": true }, \"payload\": null }")));
+        assertEquals(new SchemaAndValue(Schema.BOOLEAN_SCHEMA, true), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"boolean\" }, \"payload\": true }".getBytes()));
+        assertEquals(new SchemaAndValue(Schema.OPTIONAL_BOOLEAN_SCHEMA, null), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"boolean\", \"optional\": true }, \"payload\": null }".getBytes()));
         assertEquals(new SchemaAndValue(SchemaBuilder.bool().defaultValue(true).build(), true),
-                converter.toCopycatData(parse("{ \"schema\": { \"type\": \"boolean\", \"default\": true }, \"payload\": null }")));
+                converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"boolean\", \"default\": true }, \"payload\": null }".getBytes()));
         assertEquals(new SchemaAndValue(SchemaBuilder.bool().required().name("bool").version(2).doc("the documentation").build(), true),
-                converter.toCopycatData(parse("{ \"schema\": { \"type\": \"boolean\", \"optional\": false, \"name\": \"bool\", \"version\": 2, \"doc\": \"the documentation\"}, \"payload\": true }")));
+                converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"boolean\", \"optional\": false, \"name\": \"bool\", \"version\": 2, \"doc\": \"the documentation\"}, \"payload\": true }".getBytes()));
     }
 
     // Schema types
 
     @Test
     public void booleanToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.BOOLEAN_SCHEMA, true), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"boolean\" }, \"payload\": true }")));
-        assertEquals(new SchemaAndValue(Schema.BOOLEAN_SCHEMA, false), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"boolean\" }, \"payload\": false }")));
+        assertEquals(new SchemaAndValue(Schema.BOOLEAN_SCHEMA, true), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"boolean\" }, \"payload\": true }".getBytes()));
+        assertEquals(new SchemaAndValue(Schema.BOOLEAN_SCHEMA, false), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"boolean\" }, \"payload\": false }".getBytes()));
     }
 
     @Test
     public void byteToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.INT8_SCHEMA, (byte) 12), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"int8\" }, \"payload\": 12 }")));
+        assertEquals(new SchemaAndValue(Schema.INT8_SCHEMA, (byte) 12), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"int8\" }, \"payload\": 12 }".getBytes()));
     }
 
     @Test
     public void shortToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.INT16_SCHEMA, (short) 12), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"int16\" }, \"payload\": 12 }")));
+        assertEquals(new SchemaAndValue(Schema.INT16_SCHEMA, (short) 12), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"int16\" }, \"payload\": 12 }".getBytes()));
     }
 
     @Test
     public void intToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.INT32_SCHEMA, 12), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"int32\" }, \"payload\": 12 }")));
+        assertEquals(new SchemaAndValue(Schema.INT32_SCHEMA, 12), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"int32\" }, \"payload\": 12 }".getBytes()));
     }
 
     @Test
     public void longToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.INT64_SCHEMA, 12L), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"int64\" }, \"payload\": 12 }")));
-        assertEquals(new SchemaAndValue(Schema.INT64_SCHEMA, 4398046511104L), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"int64\" }, \"payload\": 4398046511104 }")));
+        assertEquals(new SchemaAndValue(Schema.INT64_SCHEMA, 12L), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"int64\" }, \"payload\": 12 }".getBytes()));
+        assertEquals(new SchemaAndValue(Schema.INT64_SCHEMA, 4398046511104L), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"int64\" }, \"payload\": 4398046511104 }".getBytes()));
     }
 
     @Test
     public void floatToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.FLOAT32_SCHEMA, 12.34f), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"float\" }, \"payload\": 12.34 }")));
+        assertEquals(new SchemaAndValue(Schema.FLOAT32_SCHEMA, 12.34f), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"float\" }, \"payload\": 12.34 }".getBytes()));
     }
 
     @Test
     public void doubleToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.FLOAT64_SCHEMA, 12.34), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"double\" }, \"payload\": 12.34 }")));
+        assertEquals(new SchemaAndValue(Schema.FLOAT64_SCHEMA, 12.34), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"double\" }, \"payload\": 12.34 }".getBytes()));
     }
 
 
@@ -100,69 +101,105 @@ public class JsonConverterTest {
     public void bytesToCopycat() throws UnsupportedEncodingException {
         ByteBuffer reference = ByteBuffer.wrap("test-string".getBytes("UTF-8"));
         String msg = "{ \"schema\": { \"type\": \"bytes\" }, \"payload\": \"dGVzdC1zdHJpbmc=\" }";
-        SchemaAndValue schemaAndValue = converter.toCopycatData(parse(msg));
+        SchemaAndValue schemaAndValue = converter.toCopycatData(TOPIC, msg.getBytes());
         ByteBuffer converted = ByteBuffer.wrap((byte[]) schemaAndValue.value());
         assertEquals(reference, converted);
     }
 
     @Test
     public void stringToCopycat() {
-        assertEquals(new SchemaAndValue(Schema.STRING_SCHEMA, "foo-bar-baz"), converter.toCopycatData(parse("{ \"schema\": { \"type\": \"string\" }, \"payload\": \"foo-bar-baz\" }")));
+        assertEquals(new SchemaAndValue(Schema.STRING_SCHEMA, "foo-bar-baz"), converter.toCopycatData(TOPIC, "{ \"schema\": { \"type\": \"string\" }, \"payload\": \"foo-bar-baz\" }".getBytes()));
     }
 
     @Test
     public void arrayToCopycat() {
-        JsonNode arrayJson = parse("{ \"schema\": { \"type\": \"array\", \"items\": { \"type\" : \"int32\" } }, \"payload\": [1, 2, 3] }");
-        assertEquals(new SchemaAndValue(SchemaBuilder.array(Schema.INT32_SCHEMA).build(), Arrays.asList(1, 2, 3)), converter.toCopycatData(arrayJson));
+        byte[] arrayJson = "{ \"schema\": { \"type\": \"array\", \"items\": { \"type\" : \"int32\" } }, \"payload\": [1, 2, 3] }".getBytes();
+        assertEquals(new SchemaAndValue(SchemaBuilder.array(Schema.INT32_SCHEMA).build(), Arrays.asList(1, 2, 3)), converter.toCopycatData(TOPIC, arrayJson));
     }
 
     @Test
     public void mapToCopycatStringKeys() {
-        JsonNode mapJson = parse("{ \"schema\": { \"type\": \"map\", \"keys\": { \"type\" : \"string\" }, \"values\": { \"type\" : \"int32\" } }, \"payload\": { \"key1\": 12, \"key2\": 15} }");
+        byte[] mapJson = "{ \"schema\": { \"type\": \"map\", \"keys\": { \"type\" : \"string\" }, \"values\": { \"type\" : \"int32\" } }, \"payload\": { \"key1\": 12, \"key2\": 15} }".getBytes();
         Map<String, Integer> expected = new HashMap<>();
         expected.put("key1", 12);
         expected.put("key2", 15);
-        assertEquals(new SchemaAndValue(SchemaBuilder.map(Schema.STRING_SCHEMA, Schema.INT32_SCHEMA).build(), expected), converter.toCopycatData(mapJson));
+        assertEquals(new SchemaAndValue(SchemaBuilder.map(Schema.STRING_SCHEMA, Schema.INT32_SCHEMA).build(), expected), converter.toCopycatData(TOPIC, mapJson));
     }
 
     @Test
     public void mapToCopycatNonStringKeys() {
-        JsonNode mapJson = parse("{ \"schema\": { \"type\": \"map\", \"keys\": { \"type\" : \"int32\" }, \"values\": { \"type\" : \"int32\" } }, \"payload\": [ [1, 12], [2, 15] ] }");
+        byte[] mapJson = "{ \"schema\": { \"type\": \"map\", \"keys\": { \"type\" : \"int32\" }, \"values\": { \"type\" : \"int32\" } }, \"payload\": [ [1, 12], [2, 15] ] }".getBytes();
         Map<Integer, Integer> expected = new HashMap<>();
         expected.put(1, 12);
         expected.put(2, 15);
-        assertEquals(new SchemaAndValue(SchemaBuilder.map(Schema.INT32_SCHEMA, Schema.INT32_SCHEMA).build(), expected), converter.toCopycatData(mapJson));
+        assertEquals(new SchemaAndValue(SchemaBuilder.map(Schema.INT32_SCHEMA, Schema.INT32_SCHEMA).build(), expected), converter.toCopycatData(TOPIC, mapJson));
     }
 
     @Test
     public void structToCopycat() {
-        JsonNode structJson = parse("{ \"schema\": { \"type\": \"struct\", \"fields\": [{ \"field\": \"field1\", \"type\": \"boolean\" }, { \"field\": \"field2\", \"type\": \"string\" }] }, \"payload\": { \"field1\": true, \"field2\": \"string\" } }");
+        byte[] structJson = "{ \"schema\": { \"type\": \"struct\", \"fields\": [{ \"field\": \"field1\", \"type\": \"boolean\" }, { \"field\": \"field2\", \"type\": \"string\" }] }, \"payload\": { \"field1\": true, \"field2\": \"string\" } }".getBytes();
         Schema expectedSchema = SchemaBuilder.struct().field("field1", Schema.BOOLEAN_SCHEMA).field("field2", Schema.STRING_SCHEMA).build();
         Struct expected = new Struct(expectedSchema).put("field1", true).put("field2", "string");
-        SchemaAndValue converted = converter.toCopycatData(structJson);
+        SchemaAndValue converted = converter.toCopycatData(TOPIC, structJson);
         assertEquals(new SchemaAndValue(expectedSchema, expected), converted);
     }
 
+    @Test(expected = DataException.class)
+    public void nullToCopycat() {
+        // When schemas are enabled, trying to decode a null should be an error -- we should *always* have the envelope
+        assertEquals(SchemaAndValue.NULL, converter.toCopycatData(TOPIC, null));
+    }
+
+    @Test
+    public void nullSchemaPrimitiveToCopycat() {
+        SchemaAndValue converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": null }".getBytes());
+        assertEquals(SchemaAndValue.NULL, converted);
+
+        converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": true }".getBytes());
+        assertEquals(new SchemaAndValue(null, true), converted);
+
+        // Integers: Copycat has more data types, and JSON unfortunately mixes all number types. We try to preserve
+        // info as best we can, so we always use the largest integer and floating point numbers we can and have Jackson
+        // determine if it's an integer or not
+        converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": 12 }".getBytes());
+        assertEquals(new SchemaAndValue(null, 12L), converted);
+
+        converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": 12.24 }".getBytes());
+        assertEquals(new SchemaAndValue(null, 12.24), converted);
+
+        converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": \"a string\" }".getBytes());
+        assertEquals(new SchemaAndValue(null, "a string"), converted);
+
+        converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": [1, \"2\", 3] }".getBytes());
+        assertEquals(new SchemaAndValue(null, Arrays.asList(1L, "2", 3L)), converted);
+
+        converted = converter.toCopycatData(TOPIC, "{ \"schema\": null, \"payload\": { \"field1\": 1, \"field2\": 2} }".getBytes());
+        Map<String, Long> obj = new HashMap<>();
+        obj.put("field1", 1L);
+        obj.put("field2", 2L);
+        assertEquals(new SchemaAndValue(null, obj), converted);
+    }
+
     // Schema metadata
 
     @Test
     public void testJsonSchemaMetadataTranslation() {
-        JsonNode converted = converter.fromCopycatData(Schema.BOOLEAN_SCHEMA, true);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.BOOLEAN_SCHEMA, true));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"boolean\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(true, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).booleanValue());
 
-        converted = converter.fromCopycatData(Schema.OPTIONAL_BOOLEAN_SCHEMA, null);
+        converted = parse(converter.fromCopycatData(TOPIC, Schema.OPTIONAL_BOOLEAN_SCHEMA, null));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"boolean\", \"optional\": true }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertTrue(converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).isNull());
 
-        converted = converter.fromCopycatData(SchemaBuilder.bool().defaultValue(true).build(), true);
+        converted = parse(converter.fromCopycatData(TOPIC, SchemaBuilder.bool().defaultValue(true).build(), true));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"boolean\", \"optional\": false, \"default\": true }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(true, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).booleanValue());
 
-        converted = converter.fromCopycatData(SchemaBuilder.bool().required().name("bool").version(3).doc("the documentation").build(), true);
+        converted = parse(converter.fromCopycatData(TOPIC, SchemaBuilder.bool().required().name("bool").version(3).doc("the documentation").build(), true));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"boolean\", \"optional\": false, \"name\": \"bool\", \"version\": 3, \"doc\": \"the documentation\"}"),
                 converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
@@ -173,7 +210,7 @@ public class JsonConverterTest {
 
     @Test
     public void booleanToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.BOOLEAN_SCHEMA, true);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.BOOLEAN_SCHEMA, true));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"boolean\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(true, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).booleanValue());
@@ -181,7 +218,7 @@ public class JsonConverterTest {
 
     @Test
     public void byteToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.INT8_SCHEMA, (byte) 12);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.INT8_SCHEMA, (byte) 12));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"int8\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(12, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).intValue());
@@ -189,7 +226,7 @@ public class JsonConverterTest {
 
     @Test
     public void shortToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.INT16_SCHEMA, (short) 12);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.INT16_SCHEMA, (short) 12));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"int16\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(12, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).intValue());
@@ -197,7 +234,7 @@ public class JsonConverterTest {
 
     @Test
     public void intToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.INT32_SCHEMA, 12);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.INT32_SCHEMA, 12));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"int32\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(12, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).intValue());
@@ -205,7 +242,7 @@ public class JsonConverterTest {
 
     @Test
     public void longToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.INT64_SCHEMA, 4398046511104L);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.INT64_SCHEMA, 4398046511104L));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"int64\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(4398046511104L, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).longValue());
@@ -213,7 +250,7 @@ public class JsonConverterTest {
 
     @Test
     public void floatToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.FLOAT32_SCHEMA, 12.34f);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.FLOAT32_SCHEMA, 12.34f));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"float\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(12.34f, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).floatValue(), 0.001);
@@ -221,7 +258,7 @@ public class JsonConverterTest {
 
     @Test
     public void doubleToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.FLOAT64_SCHEMA, 12.34);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.FLOAT64_SCHEMA, 12.34));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"double\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(12.34, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).doubleValue(), 0.001);
@@ -229,7 +266,7 @@ public class JsonConverterTest {
 
     @Test
     public void bytesToJson() throws IOException {
-        JsonNode converted = converter.fromCopycatData(Schema.BYTES_SCHEMA, "test-string".getBytes());
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.BYTES_SCHEMA, "test-string".getBytes()));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"bytes\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals(ByteBuffer.wrap("test-string".getBytes()),
@@ -238,7 +275,7 @@ public class JsonConverterTest {
 
     @Test
     public void stringToJson() {
-        JsonNode converted = converter.fromCopycatData(Schema.STRING_SCHEMA, "test-string");
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, Schema.STRING_SCHEMA, "test-string"));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"string\", \"optional\": false }"), converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
         assertEquals("test-string", converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).textValue());
@@ -247,7 +284,7 @@ public class JsonConverterTest {
     @Test
     public void arrayToJson() {
         Schema int32Array = SchemaBuilder.array(Schema.INT32_SCHEMA).build();
-        JsonNode converted = converter.fromCopycatData(int32Array, Arrays.asList(1, 2, 3));
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, int32Array, Arrays.asList(1, 2, 3)));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"array\", \"items\": { \"type\": \"int32\", \"optional\": false }, \"optional\": false }"),
                 converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
@@ -261,7 +298,7 @@ public class JsonConverterTest {
         Map<String, Integer> input = new HashMap<>();
         input.put("key1", 12);
         input.put("key2", 15);
-        JsonNode converted = converter.fromCopycatData(stringIntMap, input);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, stringIntMap, input));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"map\", \"keys\": { \"type\" : \"string\", \"optional\": false }, \"values\": { \"type\" : \"int32\", \"optional\": false }, \"optional\": false }"),
                 converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
@@ -275,21 +312,28 @@ public class JsonConverterTest {
         Map<Integer, Integer> input = new HashMap<>();
         input.put(1, 12);
         input.put(2, 15);
-        JsonNode converted = converter.fromCopycatData(intIntMap, input);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, intIntMap, input));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"map\", \"keys\": { \"type\" : \"int32\", \"optional\": false }, \"values\": { \"type\" : \"int32\", \"optional\": false }, \"optional\": false }"),
                 converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
-        assertEquals(JsonNodeFactory.instance.arrayNode()
-                        .add(JsonNodeFactory.instance.arrayNode().add(1).add(12))
-                        .add(JsonNodeFactory.instance.arrayNode().add(2).add(15)),
-                converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME));
+
+        assertTrue(converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).isArray());
+        ArrayNode payload = (ArrayNode) converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME);
+        assertEquals(2, payload.size());
+        Set<JsonNode> payloadEntries = new HashSet<>();
+        for (JsonNode elem : payload)
+            payloadEntries.add(elem);
+        assertEquals(new HashSet<>(Arrays.asList(JsonNodeFactory.instance.arrayNode().add(1).add(12),
+                        JsonNodeFactory.instance.arrayNode().add(2).add(15))),
+                payloadEntries
+        );
     }
 
     @Test
     public void structToJson() {
         Schema schema = SchemaBuilder.struct().field("field1", Schema.BOOLEAN_SCHEMA).field("field2", Schema.STRING_SCHEMA).build();
         Struct input = new Struct(schema).put("field1", true).put("field2", "string");
-        JsonNode converted = converter.fromCopycatData(schema, input);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, schema, input));
         validateEnvelope(converted);
         assertEquals(parse("{ \"type\": \"struct\", \"optional\": false, \"fields\": [{ \"field\": \"field1\", \"type\": \"boolean\", \"optional\": false }, { \"field\": \"field2\", \"type\": \"string\", \"optional\": false }] }"),
                 converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
@@ -299,6 +343,102 @@ public class JsonConverterTest {
                 converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME));
     }
 
+
+    @Test
+    public void nullSchemaAndPrimitiveToJson() {
+        // This still needs to do conversion of data, null schema means "anything goes"
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, null, true));
+        validateEnvelopeNullSchema(converted);
+        assertTrue(converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME).isNull());
+        assertEquals(true, converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).booleanValue());
+    }
+
+    @Test
+    public void nullSchemaAndArrayToJson() {
+        // This still needs to do conversion of data, null schema means "anything goes". Make sure we mix and match
+        // types to verify conversion still works.
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, null, Arrays.asList(1, "string", true)));
+        validateEnvelopeNullSchema(converted);
+        assertTrue(converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME).isNull());
+        assertEquals(JsonNodeFactory.instance.arrayNode().add(1).add("string").add(true),
+                converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME));
+    }
+
+    @Test
+    public void nullSchemaAndMapToJson() {
+        // This still needs to do conversion of data, null schema means "anything goes". Make sure we mix and match
+        // types to verify conversion still works.
+        Map<String, Object> input = new HashMap<>();
+        input.put("key1", 12);
+        input.put("key2", "string");
+        input.put("key3", true);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, null, input));
+        validateEnvelopeNullSchema(converted);
+        assertTrue(converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME).isNull());
+        assertEquals(JsonNodeFactory.instance.objectNode().put("key1", 12).put("key2", "string").put("key3", true),
+                converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME));
+    }
+
+    @Test
+    public void nullSchemaAndMapNonStringKeysToJson() {
+        // This still needs to do conversion of data, null schema means "anything goes". Make sure we mix and match
+        // types to verify conversion still works.
+        Map<Object, Object> input = new HashMap<>();
+        input.put("string", 12);
+        input.put(52, "string");
+        input.put(false, true);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, null, input));
+        validateEnvelopeNullSchema(converted);
+        assertTrue(converted.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME).isNull());
+        assertTrue(converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME).isArray());
+        ArrayNode payload = (ArrayNode) converted.get(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME);
+        assertEquals(3, payload.size());
+        Set<JsonNode> payloadEntries = new HashSet<>();
+        for (JsonNode elem : payload)
+            payloadEntries.add(elem);
+        assertEquals(new HashSet<>(Arrays.asList(JsonNodeFactory.instance.arrayNode().add("string").add(12),
+                        JsonNodeFactory.instance.arrayNode().add(52).add("string"),
+                        JsonNodeFactory.instance.arrayNode().add(false).add(true))),
+                payloadEntries
+        );
+    }
+
+
+    @Test(expected = DataException.class)
+    public void mismatchSchemaJson() {
+        // If we have mismatching schema info, we should properly convert to a DataException
+        converter.fromCopycatData(TOPIC, Schema.FLOAT64_SCHEMA, true);
+    }
+
+
+
+    @Test
+    public void noSchemaToCopycat() {
+        Map<String, Boolean> props = Collections.singletonMap("schemas.enable", false);
+        converter.configure(props, true);
+        assertEquals(new SchemaAndValue(null, true), converter.toCopycatData(TOPIC, "true".getBytes()));
+    }
+
+    @Test
+    public void noSchemaToJson() {
+        Map<String, Boolean> props = Collections.singletonMap("schemas.enable", false);
+        converter.configure(props, true);
+        JsonNode converted = parse(converter.fromCopycatData(TOPIC, null, true));
+        assertTrue(converted.isBoolean());
+        assertEquals(true, converted.booleanValue());
+    }
+
+
+
+    private JsonNode parse(byte[] json) {
+        try {
+            return objectMapper.readTree(json);
+        } catch (IOException e) {
+            fail("IOException during JSON parse: " + e.getMessage());
+            throw new RuntimeException("failed");
+        }
+    }
+
     private JsonNode parse(String json) {
         try {
             return objectMapper.readTree(json);
@@ -316,4 +456,13 @@ public class JsonConverterTest {
         assertTrue(env.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME).isObject());
         assertTrue(env.has(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME));
     }
+
+    private void validateEnvelopeNullSchema(JsonNode env) {
+        assertNotNull(env);
+        assertTrue(env.isObject());
+        assertEquals(2, env.size());
+        assertTrue(env.has(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME));
+        assertTrue(env.get(JsonSchema.ENVELOPE_SCHEMA_FIELD_NAME).isNull());
+        assertTrue(env.has(JsonSchema.ENVELOPE_PAYLOAD_FIELD_NAME));
+    }
 }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/cli/WorkerConfig.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/cli/WorkerConfig.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/cli/WorkerConfig.java
index 23cdf4d..a976d90 100644
--- a/copycat/runtime/src/main/java/org/apache/kafka/copycat/cli/WorkerConfig.java
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/cli/WorkerConfig.java
@@ -32,8 +32,7 @@ import java.util.Properties;
 public class WorkerConfig extends AbstractConfig {
 
     public static final String CLUSTER_CONFIG = "cluster";
-    private static final String
-            CLUSTER_CONFIG_DOC =
+    private static final String CLUSTER_CONFIG_DOC =
             "ID for this cluster, which is used to provide a namespace so multiple Copycat clusters "
                     + "or instances may co-exist while sharing a single Kafka cluster.";
     public static final String CLUSTER_DEFAULT = "copycat";
@@ -58,21 +57,13 @@ public class WorkerConfig extends AbstractConfig {
     public static final String VALUE_CONVERTER_CLASS_DOC =
             "Converter class for value Copycat data that implements the <code>Converter</code> interface.";
 
-    public static final String KEY_SERIALIZER_CLASS_CONFIG = "key.serializer";
-    public static final String KEY_SERIALIZER_CLASS_DOC =
-            "Serializer class for key that implements the <code>Serializer</code> interface.";
+    public static final String OFFSET_KEY_CONVERTER_CLASS_CONFIG = "offset.key.converter";
+    public static final String OFFSET_KEY_CONVERTER_CLASS_DOC =
+            "Converter class for offset key Copycat data that implements the <code>Converter</code> interface.";
 
-    public static final String VALUE_SERIALIZER_CLASS_CONFIG = "value.serializer";
-    public static final String VALUE_SERIALIZER_CLASS_DOC =
-            "Serializer class for value that implements the <code>Serializer</code> interface.";
-
-    public static final String KEY_DESERIALIZER_CLASS_CONFIG = "key.deserializer";
-    public static final String KEY_DESERIALIZER_CLASS_DOC =
-            "Serializer class for key that implements the <code>Deserializer</code> interface.";
-
-    public static final String VALUE_DESERIALIZER_CLASS_CONFIG = "value.deserializer";
-    public static final String VALUE_DESERIALIZER_CLASS_DOC =
-            "Deserializer class for value that implements the <code>Deserializer</code> interface.";
+    public static final String OFFSET_VALUE_CONVERTER_CLASS_CONFIG = "offset.value.converter";
+    public static final String OFFSET_VALUE_CONVERTER_CLASS_DOC =
+            "Converter class for offset value Copycat data that implements the <code>Converter</code> interface.";
 
     public static final String TASK_SHUTDOWN_GRACEFUL_TIMEOUT_MS_CONFIG
             = "task.shutdown.graceful.timeout.ms";
@@ -104,14 +95,10 @@ public class WorkerConfig extends AbstractConfig {
                         Importance.HIGH, KEY_CONVERTER_CLASS_DOC)
                 .define(VALUE_CONVERTER_CLASS_CONFIG, Type.CLASS,
                         Importance.HIGH, VALUE_CONVERTER_CLASS_DOC)
-                .define(KEY_SERIALIZER_CLASS_CONFIG, Type.CLASS,
-                        Importance.HIGH, KEY_SERIALIZER_CLASS_DOC)
-                .define(VALUE_SERIALIZER_CLASS_CONFIG, Type.CLASS,
-                        Importance.HIGH, VALUE_SERIALIZER_CLASS_DOC)
-                .define(KEY_DESERIALIZER_CLASS_CONFIG, Type.CLASS,
-                        Importance.HIGH, KEY_DESERIALIZER_CLASS_DOC)
-                .define(VALUE_DESERIALIZER_CLASS_CONFIG, Type.CLASS,
-                        Importance.HIGH, VALUE_DESERIALIZER_CLASS_DOC)
+                .define(OFFSET_KEY_CONVERTER_CLASS_CONFIG, Type.CLASS,
+                        Importance.HIGH, OFFSET_KEY_CONVERTER_CLASS_DOC)
+                .define(OFFSET_VALUE_CONVERTER_CLASS_CONFIG, Type.CLASS,
+                        Importance.HIGH, OFFSET_VALUE_CONVERTER_CLASS_DOC)
                 .define(TASK_SHUTDOWN_GRACEFUL_TIMEOUT_MS_CONFIG, Type.LONG,
                         TASK_SHUTDOWN_GRACEFUL_TIMEOUT_MS_DEFAULT, Importance.LOW,
                         TASK_SHUTDOWN_GRACEFUL_TIMEOUT_MS_DOC)

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/Worker.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/Worker.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/Worker.java
index 704470a..6cbce0b 100644
--- a/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/Worker.java
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/Worker.java
@@ -17,8 +17,6 @@
 
 package org.apache.kafka.copycat.runtime;
 
-import org.apache.kafka.common.serialization.Deserializer;
-import org.apache.kafka.common.serialization.Serializer;
 import org.apache.kafka.common.utils.SystemTime;
 import org.apache.kafka.common.utils.Time;
 import org.apache.kafka.clients.producer.KafkaProducer;
@@ -47,34 +45,36 @@ import java.util.Properties;
  * Since each task has a dedicated thread, this is mainly just a container for them.
  * </p>
  */
-public class Worker<K, V> {
+public class Worker {
     private static final Logger log = LoggerFactory.getLogger(Worker.class);
 
     private Time time;
     private WorkerConfig config;
-    private Converter<K> keyConverter;
-    private Converter<V> valueConverter;
+    private Converter keyConverter;
+    private Converter valueConverter;
+    private Converter offsetKeyConverter;
+    private Converter offsetValueConverter;
     private OffsetBackingStore offsetBackingStore;
-    private Serializer<K> offsetKeySerializer;
-    private Serializer<V> offsetValueSerializer;
-    private Deserializer<K> offsetKeyDeserializer;
-    private Deserializer<V> offsetValueDeserializer;
     private HashMap<ConnectorTaskId, WorkerTask> tasks = new HashMap<>();
-    private KafkaProducer<K, V> producer;
+    private KafkaProducer<byte[], byte[]> producer;
     private SourceTaskOffsetCommitter sourceTaskOffsetCommitter;
 
     public Worker(WorkerConfig config) {
-        this(new SystemTime(), config, null, null, null, null, null);
+        this(new SystemTime(), config, null);
     }
 
     @SuppressWarnings("unchecked")
-    public Worker(Time time, WorkerConfig config, OffsetBackingStore offsetBackingStore,
-                  Serializer offsetKeySerializer, Serializer offsetValueSerializer,
-                  Deserializer offsetKeyDeserializer, Deserializer offsetValueDeserializer) {
+    public Worker(Time time, WorkerConfig config, OffsetBackingStore offsetBackingStore) {
         this.time = time;
         this.config = config;
         this.keyConverter = config.getConfiguredInstance(WorkerConfig.KEY_CONVERTER_CLASS_CONFIG, Converter.class);
+        this.keyConverter.configure(config.originalsWithPrefix("key.converter."), true);
         this.valueConverter = config.getConfiguredInstance(WorkerConfig.VALUE_CONVERTER_CLASS_CONFIG, Converter.class);
+        this.valueConverter.configure(config.originalsWithPrefix("value.converter."), false);
+        this.offsetKeyConverter = config.getConfiguredInstance(WorkerConfig.OFFSET_KEY_CONVERTER_CLASS_CONFIG, Converter.class);
+        this.offsetKeyConverter.configure(config.originalsWithPrefix("offset.key.converter."), true);
+        this.offsetValueConverter = config.getConfiguredInstance(WorkerConfig.OFFSET_VALUE_CONVERTER_CLASS_CONFIG, Converter.class);
+        this.offsetValueConverter.configure(config.originalsWithPrefix("offset.value.converter."), false);
 
         if (offsetBackingStore != null) {
             this.offsetBackingStore = offsetBackingStore;
@@ -82,34 +82,6 @@ public class Worker<K, V> {
             this.offsetBackingStore = new FileOffsetBackingStore();
             this.offsetBackingStore.configure(config.originals());
         }
-
-        if (offsetKeySerializer != null) {
-            this.offsetKeySerializer = offsetKeySerializer;
-        } else {
-            this.offsetKeySerializer = config.getConfiguredInstance(WorkerConfig.KEY_SERIALIZER_CLASS_CONFIG, Serializer.class);
-            this.offsetKeySerializer.configure(config.originals(), true);
-        }
-
-        if (offsetValueSerializer != null) {
-            this.offsetValueSerializer = offsetValueSerializer;
-        } else {
-            this.offsetValueSerializer = config.getConfiguredInstance(WorkerConfig.VALUE_SERIALIZER_CLASS_CONFIG, Serializer.class);
-            this.offsetValueSerializer.configure(config.originals(), false);
-        }
-
-        if (offsetKeyDeserializer != null) {
-            this.offsetKeyDeserializer = offsetKeyDeserializer;
-        } else {
-            this.offsetKeyDeserializer = config.getConfiguredInstance(WorkerConfig.KEY_DESERIALIZER_CLASS_CONFIG, Deserializer.class);
-            this.offsetKeyDeserializer.configure(config.originals(), true);
-        }
-
-        if (offsetValueDeserializer != null) {
-            this.offsetValueDeserializer = offsetValueDeserializer;
-        } else {
-            this.offsetValueDeserializer = config.getConfiguredInstance(WorkerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, Deserializer.class);
-            this.offsetValueDeserializer.configure(config.originals(), false);
-        }
     }
 
     public void start() {
@@ -119,8 +91,8 @@ public class Worker<K, V> {
 
         Map<String, Object> producerProps = new HashMap<>();
         producerProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, Utils.join(config.getList(WorkerConfig.BOOTSTRAP_SERVERS_CONFIG), ","));
-        producerProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, config.getClass(WorkerConfig.KEY_SERIALIZER_CLASS_CONFIG).getName());
-        producerProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, config.getClass(WorkerConfig.VALUE_SERIALIZER_CLASS_CONFIG).getName());
+        producerProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArraySerializer");
+        producerProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArraySerializer");
         for (String propName : unusedConfigs.stringPropertyNames()) {
             producerProps.put(propName, unusedConfigs.getProperty(propName));
         }
@@ -188,14 +160,14 @@ public class Worker<K, V> {
         final WorkerTask workerTask;
         if (task instanceof SourceTask) {
             SourceTask sourceTask = (SourceTask) task;
-            OffsetStorageReader offsetReader = new OffsetStorageReaderImpl<>(offsetBackingStore, id.connector(),
-                    keyConverter, valueConverter, offsetKeySerializer, offsetValueDeserializer);
-            OffsetStorageWriter<K, V> offsetWriter = new OffsetStorageWriter<>(offsetBackingStore, id.connector(),
-                    keyConverter, valueConverter, offsetKeySerializer, offsetValueSerializer);
-            workerTask = new WorkerSourceTask<>(id, sourceTask, keyConverter, valueConverter, producer,
+            OffsetStorageReader offsetReader = new OffsetStorageReaderImpl(offsetBackingStore, id.connector(),
+                    offsetKeyConverter, offsetValueConverter);
+            OffsetStorageWriter offsetWriter = new OffsetStorageWriter(offsetBackingStore, id.connector(),
+                    offsetKeyConverter, offsetValueConverter);
+            workerTask = new WorkerSourceTask(id, sourceTask, keyConverter, valueConverter, producer,
                     offsetReader, offsetWriter, config, time);
         } else if (task instanceof SinkTask) {
-            workerTask = new WorkerSinkTask<>(id, (SinkTask) task, config, keyConverter, valueConverter, time);
+            workerTask = new WorkerSinkTask(id, (SinkTask) task, config, keyConverter, valueConverter, time);
         } else {
             log.error("Tasks must be a subclass of either SourceTask or SinkTask", task);
             throw new CopycatException("Tasks must be a subclass of either SourceTask or SinkTask");

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSinkTask.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSinkTask.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSinkTask.java
index dfb1f96..7e71fb8 100644
--- a/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSinkTask.java
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSinkTask.java
@@ -38,21 +38,21 @@ import java.util.concurrent.TimeUnit;
 /**
  * WorkerTask that uses a SinkTask to export data from Kafka.
  */
-class WorkerSinkTask<K, V> implements WorkerTask {
+class WorkerSinkTask implements WorkerTask {
     private static final Logger log = LoggerFactory.getLogger(WorkerSinkTask.class);
 
     private final ConnectorTaskId id;
     private final SinkTask task;
     private final WorkerConfig workerConfig;
     private final Time time;
-    private final Converter<K> keyConverter;
-    private final Converter<V> valueConverter;
+    private final Converter keyConverter;
+    private final Converter valueConverter;
     private WorkerSinkTaskThread workThread;
-    private KafkaConsumer<K, V> consumer;
+    private KafkaConsumer<byte[], byte[]> consumer;
     private final SinkTaskContext context;
 
     public WorkerSinkTask(ConnectorTaskId id, SinkTask task, WorkerConfig workerConfig,
-                          Converter<K> keyConverter, Converter<V> valueConverter, Time time) {
+                          Converter keyConverter, Converter valueConverter, Time time) {
         this.id = id;
         this.task = task;
         this.workerConfig = workerConfig;
@@ -107,7 +107,7 @@ class WorkerSinkTask<K, V> implements WorkerTask {
     public void poll(long timeoutMs) {
         try {
             log.trace("{} polling consumer with timeout {} ms", id, timeoutMs);
-            ConsumerRecords<K, V> msgs = consumer.poll(timeoutMs);
+            ConsumerRecords<byte[], byte[]> msgs = consumer.poll(timeoutMs);
             log.trace("{} polling returned {} messages", id, msgs.count());
             deliverMessages(msgs);
         } catch (ConsumerWakeupException we) {
@@ -154,7 +154,7 @@ class WorkerSinkTask<K, V> implements WorkerTask {
         return workerConfig;
     }
 
-    private KafkaConsumer<K, V> createConsumer(Properties taskProps) {
+    private KafkaConsumer<byte[], byte[]> createConsumer(Properties taskProps) {
         String topicsStr = taskProps.getProperty(SinkTask.TOPICS_CONFIG);
         if (topicsStr == null || topicsStr.isEmpty())
             throw new CopycatException("Sink tasks require a list of topics.");
@@ -168,12 +168,10 @@ class WorkerSinkTask<K, V> implements WorkerTask {
                 Utils.join(workerConfig.getList(WorkerConfig.BOOTSTRAP_SERVERS_CONFIG), ","));
         props.setProperty(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false");
         props.setProperty(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
-        props.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
-                workerConfig.getClass(WorkerConfig.KEY_DESERIALIZER_CLASS_CONFIG).getName());
-        props.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
-                workerConfig.getClass(WorkerConfig.VALUE_DESERIALIZER_CLASS_CONFIG).getName());
+        props.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArrayDeserializer");
+        props.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArrayDeserializer");
 
-        KafkaConsumer<K, V> newConsumer;
+        KafkaConsumer<byte[], byte[]> newConsumer;
         try {
             newConsumer = new KafkaConsumer<>(props);
         } catch (Throwable t) {
@@ -202,14 +200,14 @@ class WorkerSinkTask<K, V> implements WorkerTask {
         return new WorkerSinkTaskThread(this, "WorkerSinkTask-" + id, time, workerConfig);
     }
 
-    private void deliverMessages(ConsumerRecords<K, V> msgs) {
+    private void deliverMessages(ConsumerRecords<byte[], byte[]> msgs) {
         // Finally, deliver this batch to the sink
         if (msgs.count() > 0) {
             List<SinkRecord> records = new ArrayList<>();
-            for (ConsumerRecord<K, V> msg : msgs) {
+            for (ConsumerRecord<byte[], byte[]> msg : msgs) {
                 log.trace("Consuming message with key {}, value {}", msg.key(), msg.value());
-                SchemaAndValue keyAndSchema = msg.key() != null ? keyConverter.toCopycatData(msg.key()) : SchemaAndValue.NULL;
-                SchemaAndValue valueAndSchema = msg.value() != null ? valueConverter.toCopycatData(msg.value()) : SchemaAndValue.NULL;
+                SchemaAndValue keyAndSchema = keyConverter.toCopycatData(msg.topic(), msg.key());
+                SchemaAndValue valueAndSchema = valueConverter.toCopycatData(msg.topic(), msg.value());
                 records.add(
                         new SinkRecord(msg.topic(), msg.partition(),
                                 keyAndSchema.schema(), keyAndSchema.value(),

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSourceTask.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSourceTask.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSourceTask.java
index 14b9c3a..ee0a532 100644
--- a/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSourceTask.java
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/runtime/WorkerSourceTask.java
@@ -23,7 +23,6 @@ import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.ProducerRecord;
 import org.apache.kafka.clients.producer.RecordMetadata;
 import org.apache.kafka.copycat.cli.WorkerConfig;
-import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.source.SourceRecord;
 import org.apache.kafka.copycat.source.SourceTask;
 import org.apache.kafka.copycat.source.SourceTaskContext;
@@ -46,33 +45,31 @@ import java.util.concurrent.TimeoutException;
 /**
  * WorkerTask that uses a SourceTask to ingest data into Kafka.
  */
-class WorkerSourceTask<K, V> implements WorkerTask {
+class WorkerSourceTask implements WorkerTask {
     private static final Logger log = LoggerFactory.getLogger(WorkerSourceTask.class);
 
     private ConnectorTaskId id;
     private SourceTask task;
-    private final Converter<K> keyConverter;
-    private final Converter<V> valueConverter;
-    private KafkaProducer<K, V> producer;
+    private final Converter keyConverter;
+    private final Converter valueConverter;
+    private KafkaProducer<byte[], byte[]> producer;
     private WorkerSourceTaskThread workThread;
     private OffsetStorageReader offsetReader;
-    private OffsetStorageWriter<K, V> offsetWriter;
+    private OffsetStorageWriter offsetWriter;
     private final WorkerConfig workerConfig;
     private final Time time;
 
     // Use IdentityHashMap to ensure correctness with duplicate records. This is a HashMap because
     // there is no IdentityHashSet.
-    private IdentityHashMap<ProducerRecord<K, V>, ProducerRecord<K, V>>
-            outstandingMessages;
+    private IdentityHashMap<ProducerRecord<byte[], byte[]>, ProducerRecord<byte[], byte[]>> outstandingMessages;
     // A second buffer is used while an offset flush is running
-    private IdentityHashMap<ProducerRecord<K, V>, ProducerRecord<K, V>>
-            outstandingMessagesBacklog;
+    private IdentityHashMap<ProducerRecord<byte[], byte[]>, ProducerRecord<byte[], byte[]>> outstandingMessagesBacklog;
     private boolean flushing;
 
     public WorkerSourceTask(ConnectorTaskId id, SourceTask task,
-                            Converter<K> keyConverter, Converter<V> valueConverter,
-                            KafkaProducer<K, V> producer,
-                            OffsetStorageReader offsetReader, OffsetStorageWriter<K, V> offsetWriter,
+                            Converter keyConverter, Converter valueConverter,
+                            KafkaProducer<byte[], byte[]> producer,
+                            OffsetStorageReader offsetReader, OffsetStorageWriter offsetWriter,
                             WorkerConfig workerConfig, Time time) {
         this.id = id;
         this.task = task;
@@ -132,10 +129,9 @@ class WorkerSourceTask<K, V> implements WorkerTask {
      */
     private synchronized void sendRecords(List<SourceRecord> records) {
         for (SourceRecord record : records) {
-            K key = (record.keySchema() != null) ? keyConverter.fromCopycatData(record.keySchema(), record.key()) : null;
-            V value = (record.valueSchema() != null) ? valueConverter.fromCopycatData(record.valueSchema(), record.value()) : null;
-            final ProducerRecord<K, V> producerRecord = new ProducerRecord<>(
-                    record.topic(), record.kafkaPartition(), key, value);
+            byte[] key = keyConverter.fromCopycatData(record.topic(), record.keySchema(), record.key());
+            byte[] value = valueConverter.fromCopycatData(record.topic(), record.valueSchema(), record.value());
+            final ProducerRecord<byte[], byte[]> producerRecord = new ProducerRecord<>(record.topic(), record.kafkaPartition(), key, value);
             log.trace("Appending record with key {}, value {}", record.key(), record.value());
             if (!flushing) {
                 outstandingMessages.put(producerRecord, producerRecord);
@@ -158,13 +154,12 @@ class WorkerSourceTask<K, V> implements WorkerTask {
                         }
                     });
             // Offsets are converted & serialized in the OffsetWriter
-            offsetWriter.offset(new SchemaAndValue(record.sourcePartitionSchema(), record.sourcePartition()),
-                    new SchemaAndValue(record.sourceOffsetSchema(), record.sourceOffset()));
+            offsetWriter.offset(record.sourcePartition(), record.sourceOffset());
         }
     }
 
-    private synchronized void recordSent(final ProducerRecord<K, V> record) {
-        ProducerRecord<K, V> removed = outstandingMessages.remove(record);
+    private synchronized void recordSent(final ProducerRecord<byte[], byte[]> record) {
+        ProducerRecord<byte[], byte[]> removed = outstandingMessages.remove(record);
         // While flushing, we may also see callbacks for items in the backlog
         if (removed == null && flushing)
             removed = outstandingMessagesBacklog.remove(record);
@@ -276,7 +271,7 @@ class WorkerSourceTask<K, V> implements WorkerTask {
 
     private void finishSuccessfulFlush() {
         // If we were successful, we can just swap instead of replacing items back into the original map
-        IdentityHashMap<ProducerRecord<K, V>, ProducerRecord<K, V>> temp = outstandingMessages;
+        IdentityHashMap<ProducerRecord<byte[], byte[]>, ProducerRecord<byte[], byte[]>> temp = outstandingMessages;
         outstandingMessages = outstandingMessagesBacklog;
         outstandingMessagesBacklog = temp;
         flushing = false;

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReaderImpl.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReaderImpl.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReaderImpl.java
index 237eda6..7521955 100644
--- a/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReaderImpl.java
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageReaderImpl.java
@@ -17,8 +17,6 @@
 
 package org.apache.kafka.copycat.storage;
 
-import org.apache.kafka.common.serialization.Deserializer;
-import org.apache.kafka.common.serialization.Serializer;
 import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.errors.CopycatException;
 import org.slf4j.Logger;
@@ -35,39 +33,36 @@ import java.util.Map;
  * directly, the interface is only separate from this implementation because it needs to be
  * included in the public API package.
  */
-public class OffsetStorageReaderImpl<K, V> implements OffsetStorageReader {
+public class OffsetStorageReaderImpl implements OffsetStorageReader {
     private static final Logger log = LoggerFactory.getLogger(OffsetStorageReaderImpl.class);
 
     private final OffsetBackingStore backingStore;
     private final String namespace;
-    private final Converter<K> keyConverter;
-    private final Converter<V> valueConverter;
-    private final Serializer<K> keySerializer;
-    private final Deserializer<V> valueDeserializer;
+    private final Converter keyConverter;
+    private final Converter valueConverter;
 
     public OffsetStorageReaderImpl(OffsetBackingStore backingStore, String namespace,
-                                   Converter<K> keyConverter, Converter<V> valueConverter,
-                                   Serializer<K> keySerializer, Deserializer<V> valueDeserializer) {
+                                   Converter keyConverter, Converter valueConverter) {
         this.backingStore = backingStore;
         this.namespace = namespace;
         this.keyConverter = keyConverter;
         this.valueConverter = valueConverter;
-        this.keySerializer = keySerializer;
-        this.valueDeserializer = valueDeserializer;
     }
 
     @Override
-    public SchemaAndValue offset(SchemaAndValue partition) {
+    public <T> Map<String, Object> offset(Map<String, T> partition) {
         return offsets(Arrays.asList(partition)).get(partition);
     }
 
     @Override
-    public Map<SchemaAndValue, SchemaAndValue> offsets(Collection<SchemaAndValue> partitions) {
+    public <T> Map<Map<String, T>, Map<String, Object>> offsets(Collection<Map<String, T>> partitions) {
         // Serialize keys so backing store can work with them
-        Map<ByteBuffer, SchemaAndValue> serializedToOriginal = new HashMap<>(partitions.size());
-        for (SchemaAndValue key : partitions) {
+        Map<ByteBuffer, Map<String, T>> serializedToOriginal = new HashMap<>(partitions.size());
+        for (Map<String, T> key : partitions) {
             try {
-                byte[] keySerialized = keySerializer.serialize(namespace, keyConverter.fromCopycatData(key.schema(), key.value()));
+                // Offsets are treated as schemaless, their format is only validated here (and the returned value below)
+                OffsetUtils.validateFormat(key);
+                byte[] keySerialized = keyConverter.fromCopycatData(namespace, null, key);
                 ByteBuffer keyBuffer = (keySerialized != null) ? ByteBuffer.wrap(keySerialized) : null;
                 serializedToOriginal.put(keyBuffer, key);
             } catch (Throwable t) {
@@ -87,7 +82,7 @@ public class OffsetStorageReaderImpl<K, V> implements OffsetStorageReader {
         }
 
         // Deserialize all the values and map back to the original keys
-        Map<SchemaAndValue, SchemaAndValue> result = new HashMap<>(partitions.size());
+        Map<Map<String, T>, Map<String, Object>> result = new HashMap<>(partitions.size());
         for (Map.Entry<ByteBuffer, ByteBuffer> rawEntry : raw.entrySet()) {
             try {
                 // Since null could be a valid key, explicitly check whether map contains the key
@@ -96,12 +91,12 @@ public class OffsetStorageReaderImpl<K, V> implements OffsetStorageReader {
                             + "store may have returned invalid data", rawEntry.getKey());
                     continue;
                 }
-                SchemaAndValue origKey = serializedToOriginal.get(rawEntry.getKey());
-                SchemaAndValue deserializedValue = valueConverter.toCopycatData(
-                        valueDeserializer.deserialize(namespace, rawEntry.getValue().array())
-                );
+                Map<String, T> origKey = serializedToOriginal.get(rawEntry.getKey());
+                SchemaAndValue deserializedSchemaAndValue = valueConverter.toCopycatData(namespace, rawEntry.getValue().array());
+                Object deserializedValue = deserializedSchemaAndValue.value();
+                OffsetUtils.validateFormat(deserializedValue);
 
-                result.put(origKey, deserializedValue);
+                result.put(origKey, (Map<String, Object>) deserializedValue);
             } catch (Throwable t) {
                 log.error("CRITICAL: Failed to deserialize offset data when getting offsets for task with"
                         + " namespace {}. No value for this data will be returned, which may break the "

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageWriter.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageWriter.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageWriter.java
index 4fb75e7..be8c718 100644
--- a/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageWriter.java
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetStorageWriter.java
@@ -17,16 +17,13 @@
 
 package org.apache.kafka.copycat.storage;
 
-import org.apache.kafka.common.serialization.Serializer;
-import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.errors.CopycatException;
 import org.apache.kafka.copycat.util.Callback;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.nio.ByteBuffer;
-import java.util.HashMap;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.Future;
 
 /**
@@ -64,32 +61,27 @@ import java.util.concurrent.Future;
  * This class is not thread-safe. It should only be accessed from a Task's processing thread.
  * </p>
  */
-public class OffsetStorageWriter<K, V> {
+public class OffsetStorageWriter {
     private static final Logger log = LoggerFactory.getLogger(OffsetStorageWriter.class);
 
     private final OffsetBackingStore backingStore;
-    private final Converter<K> keyConverter;
-    private final Converter<V> valueConverter;
-    private final Serializer<K> keySerializer;
-    private final Serializer<V> valueSerializer;
+    private final Converter keyConverter;
+    private final Converter valueConverter;
     private final String namespace;
     // Offset data in Copycat format
-    private Map<SchemaAndValue, SchemaAndValue> data = new HashMap<>();
+    private Map<Map<String, Object>, Map<String, Object>> data = new HashMap<>();
 
     // Not synchronized, should only be accessed by flush thread
-    private Map<SchemaAndValue, SchemaAndValue> toFlush = null;
+    private Map<Map<String, Object>, Map<String, Object>> toFlush = null;
     // Unique ID for each flush request to handle callbacks after timeouts
     private long currentFlushId = 0;
 
     public OffsetStorageWriter(OffsetBackingStore backingStore,
-                               String namespace, Converter<K> keyConverter, Converter<V> valueConverter,
-                               Serializer<K> keySerializer, Serializer<V> valueSerializer) {
+                               String namespace, Converter keyConverter, Converter valueConverter) {
         this.backingStore = backingStore;
         this.namespace = namespace;
         this.keyConverter = keyConverter;
         this.valueConverter = valueConverter;
-        this.keySerializer = keySerializer;
-        this.valueSerializer = valueSerializer;
     }
 
     /**
@@ -97,8 +89,8 @@ public class OffsetStorageWriter<K, V> {
      * @param partition the partition to store an offset for
      * @param offset the offset
      */
-    public synchronized void offset(SchemaAndValue partition, SchemaAndValue offset) {
-        data.put(partition, offset);
+    public synchronized void offset(Map<String, ?> partition, Map<String, ?> offset) {
+        data.put((Map<String, Object>) partition, (Map<String, Object>) offset);
     }
 
     private boolean flushing() {
@@ -142,10 +134,14 @@ public class OffsetStorageWriter<K, V> {
         Map<ByteBuffer, ByteBuffer> offsetsSerialized;
         try {
             offsetsSerialized = new HashMap<>();
-            for (Map.Entry<SchemaAndValue, SchemaAndValue> entry : toFlush.entrySet()) {
-                byte[] key = keySerializer.serialize(namespace, keyConverter.fromCopycatData(entry.getKey().schema(), entry.getKey().value()));
+            for (Map.Entry<Map<String, Object>, Map<String, Object>> entry : toFlush.entrySet()) {
+                // Offsets are specified as schemaless to the converter, using whatever internal schema is appropriate
+                // for that data. The only enforcement of the format is here.
+                OffsetUtils.validateFormat(entry.getKey());
+                OffsetUtils.validateFormat(entry.getValue());
+                byte[] key = keyConverter.fromCopycatData(namespace, null, entry.getKey());
                 ByteBuffer keyBuffer = (key != null) ? ByteBuffer.wrap(key) : null;
-                byte[] value = valueSerializer.serialize(namespace, valueConverter.fromCopycatData(entry.getValue().schema(), entry.getValue().value()));
+                byte[] value = valueConverter.fromCopycatData(namespace, null, entry.getValue());
                 ByteBuffer valueBuffer = (value != null) ? ByteBuffer.wrap(value) : null;
                 offsetsSerialized.put(keyBuffer, valueBuffer);
             }
@@ -155,6 +151,7 @@ public class OffsetStorageWriter<K, V> {
             log.error("CRITICAL: Failed to serialize offset data, making it impossible to commit "
                     + "offsets under namespace {}. This likely won't recover unless the "
                     + "unserializable partition or offset information is overwritten.", namespace);
+            log.error("Cause of serialization failure:", t);
             callback.onCompletion(t, null);
             return null;
         }

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetUtils.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetUtils.java b/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetUtils.java
new file mode 100644
index 0000000..bd3a87b
--- /dev/null
+++ b/copycat/runtime/src/main/java/org/apache/kafka/copycat/storage/OffsetUtils.java
@@ -0,0 +1,46 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+package org.apache.kafka.copycat.storage;
+
+import org.apache.kafka.copycat.data.CopycatSchema;
+import org.apache.kafka.copycat.data.Schema;
+import org.apache.kafka.copycat.errors.DataException;
+
+import java.util.Map;
+
+public class OffsetUtils {
+    public static void validateFormat(Object offsetData) {
+        if (!(offsetData instanceof Map))
+            throw new DataException("Offsets must be specified as a Map");
+        validateFormat((Map<Object, Object>) offsetData);
+    }
+
+    public static <K, V> void validateFormat(Map<K, V> offsetData) {
+        for (Map.Entry<K, V> entry : offsetData.entrySet()) {
+            if (!(entry.getKey() instanceof String))
+                throw new DataException("Offsets may only use String keys");
+
+            Object value = entry.getValue();
+            if (value == null)
+                continue;
+            Schema.Type schemaType = CopycatSchema.schemaType(value.getClass());
+            if (!schemaType.isPrimitive())
+                throw new DataException("Offsets may only contain primitive types as values, but field " + entry.getKey() + " contains " + schemaType);
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSinkTaskTest.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSinkTaskTest.java b/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSinkTaskTest.java
index 54e9bc6..542ed76 100644
--- a/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSinkTaskTest.java
+++ b/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSinkTaskTest.java
@@ -67,10 +67,10 @@ public class WorkerSinkTaskTest extends ThreadedTest {
     private Time time;
     @Mock private SinkTask sinkTask;
     private WorkerConfig workerConfig;
-    @Mock private Converter<byte[]> keyConverter;
+    @Mock private Converter keyConverter;
     @Mock
-    private Converter<byte[]> valueConverter;
-    private WorkerSinkTask<Integer, String> workerTask;
+    private Converter valueConverter;
+    private WorkerSinkTask workerTask;
     @Mock private KafkaConsumer<byte[], byte[]> consumer;
     private WorkerSinkTaskThread workerThread;
 
@@ -84,10 +84,10 @@ public class WorkerSinkTaskTest extends ThreadedTest {
         Properties workerProps = new Properties();
         workerProps.setProperty("key.converter", "org.apache.kafka.copycat.json.JsonConverter");
         workerProps.setProperty("value.converter", "org.apache.kafka.copycat.json.JsonConverter");
-        workerProps.setProperty("key.serializer", "org.apache.kafka.copycat.json.JsonSerializer");
-        workerProps.setProperty("value.serializer", "org.apache.kafka.copycat.json.JsonSerializer");
-        workerProps.setProperty("key.deserializer", "org.apache.kafka.copycat.json.JsonDeserializer");
-        workerProps.setProperty("value.deserializer", "org.apache.kafka.copycat.json.JsonDeserializer");
+        workerProps.setProperty("offset.key.converter", "org.apache.kafka.copycat.json.JsonConverter");
+        workerProps.setProperty("offset.value.converter", "org.apache.kafka.copycat.json.JsonConverter");
+        workerProps.setProperty("offset.key.converter.schemas.enable", "false");
+        workerProps.setProperty("offset.value.converter.schemas.enable", "false");
         workerConfig = new WorkerConfig(workerProps);
         workerTask = PowerMock.createPartialMock(
                 WorkerSinkTask.class, new String[]{"createConsumer", "createWorkerThread"},
@@ -138,12 +138,12 @@ public class WorkerSinkTaskTest extends ThreadedTest {
 
         ConsumerRecords<byte[], byte[]> records = new ConsumerRecords<>(
                 Collections.singletonMap(
-                        new TopicPartition("topic", 0),
-                        Collections.singletonList(new ConsumerRecord<>("topic", 0, 0, RAW_KEY, RAW_VALUE))));
+                        new TopicPartition(TOPIC, 0),
+                        Collections.singletonList(new ConsumerRecord<>(TOPIC, 0, 0, RAW_KEY, RAW_VALUE))));
 
         // Exact data doesn't matter, but should be passed directly to sink task
-        EasyMock.expect(keyConverter.toCopycatData(RAW_KEY)).andReturn(record);
-        EasyMock.expect(valueConverter.toCopycatData(RAW_VALUE)).andReturn(record);
+        EasyMock.expect(keyConverter.toCopycatData(EasyMock.eq(TOPIC), EasyMock.aryEq(RAW_KEY))).andReturn(record);
+        EasyMock.expect(valueConverter.toCopycatData(EasyMock.eq(TOPIC), EasyMock.aryEq(RAW_VALUE))).andReturn(record);
         Capture<Collection<SinkRecord>> capturedRecords
                 = EasyMock.newCapture(CaptureType.ALL);
         sinkTask.put(EasyMock.capture(capturedRecords));
@@ -320,8 +320,8 @@ public class WorkerSinkTaskTest extends ThreadedTest {
                         return records;
                     }
                 });
-        EasyMock.expect(keyConverter.toCopycatData(RAW_KEY)).andReturn(new SchemaAndValue(KEY_SCHEMA, KEY)).anyTimes();
-        EasyMock.expect(valueConverter.toCopycatData(RAW_VALUE)).andReturn(new SchemaAndValue(VALUE_SCHEMA, VALUE)).anyTimes();
+        EasyMock.expect(keyConverter.toCopycatData(TOPIC, RAW_KEY)).andReturn(new SchemaAndValue(KEY_SCHEMA, KEY)).anyTimes();
+        EasyMock.expect(valueConverter.toCopycatData(TOPIC, RAW_VALUE)).andReturn(new SchemaAndValue(VALUE_SCHEMA, VALUE)).anyTimes();
         Capture<Collection<SinkRecord>> capturedRecords = EasyMock.newCapture(CaptureType.ALL);
         sinkTask.put(EasyMock.capture(capturedRecords));
         EasyMock.expectLastCall().anyTimes();

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSourceTaskTest.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSourceTaskTest.java b/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSourceTaskTest.java
index 018aa94..3ff3a62 100644
--- a/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSourceTaskTest.java
+++ b/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerSourceTaskTest.java
@@ -24,7 +24,6 @@ import org.apache.kafka.clients.producer.RecordMetadata;
 import org.apache.kafka.common.TopicPartition;
 import org.apache.kafka.copycat.cli.WorkerConfig;
 import org.apache.kafka.copycat.data.Schema;
-import org.apache.kafka.copycat.data.SchemaAndValue;
 import org.apache.kafka.copycat.source.SourceRecord;
 import org.apache.kafka.copycat.source.SourceTask;
 import org.apache.kafka.copycat.source.SourceTaskContext;
@@ -45,11 +44,7 @@ import org.powermock.api.easymock.annotation.Mock;
 import org.powermock.modules.junit4.PowerMockRunner;
 import org.powermock.reflect.Whitebox;
 
-import java.nio.ByteBuffer;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Properties;
+import java.util.*;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
@@ -59,37 +54,36 @@ import static org.junit.Assert.*;
 
 @RunWith(PowerMockRunner.class)
 public class WorkerSourceTaskTest extends ThreadedTest {
-    private static final Schema PARTITION_SCHEMA = Schema.BYTES_SCHEMA;
-    private static final byte[] PARTITION_BYTES = "partition".getBytes();
-    private static final Schema OFFSET_SCHEMA = Schema.BYTES_SCHEMA;
-    private static final byte[] OFFSET_BYTES = "offset-1".getBytes();
+    private static final String TOPIC = "topic";
+    private static final Map<String, byte[]> PARTITION = Collections.singletonMap("key", "partition".getBytes());
+    private static final Map<String, Integer> OFFSET = Collections.singletonMap("key", 12);
 
     // Copycat-format data
     private static final Schema KEY_SCHEMA = Schema.INT32_SCHEMA;
     private static final Integer KEY = -1;
     private static final Schema RECORD_SCHEMA = Schema.INT64_SCHEMA;
     private static final Long RECORD = 12L;
-    // Native-formatted data. The actual format of this data doesn't matter -- we just want to see that the right version
+    // Serialized data. The actual format of this data doesn't matter -- we just want to see that the right version
     // is used in the right place.
-    private static final ByteBuffer CONVERTED_KEY = ByteBuffer.wrap("converted-key".getBytes());
-    private static final String CONVERTED_RECORD = "converted-record";
+    private static final byte[] SERIALIZED_KEY = "converted-key".getBytes();
+    private static final byte[] SERIALIZED_RECORD = "converted-record".getBytes();
 
     private ConnectorTaskId taskId = new ConnectorTaskId("job", 0);
     private WorkerConfig config;
     @Mock private SourceTask sourceTask;
-    @Mock private Converter<ByteBuffer> keyConverter;
-    @Mock private Converter<String> valueConverter;
-    @Mock private KafkaProducer<ByteBuffer, String> producer;
+    @Mock private Converter keyConverter;
+    @Mock private Converter valueConverter;
+    @Mock private KafkaProducer<byte[], byte[]> producer;
     @Mock private OffsetStorageReader offsetReader;
-    @Mock private OffsetStorageWriter<ByteBuffer, String> offsetWriter;
-    private WorkerSourceTask<ByteBuffer, String> workerTask;
+    @Mock private OffsetStorageWriter offsetWriter;
+    private WorkerSourceTask workerTask;
     @Mock private Future<RecordMetadata> sendFuture;
 
     private Capture<org.apache.kafka.clients.producer.Callback> producerCallbacks;
 
     private static final Properties EMPTY_TASK_PROPS = new Properties();
     private static final List<SourceRecord> RECORDS = Arrays.asList(
-            new SourceRecord(PARTITION_SCHEMA, PARTITION_BYTES, OFFSET_SCHEMA, OFFSET_BYTES, "topic", null, KEY_SCHEMA, KEY, RECORD_SCHEMA, RECORD)
+            new SourceRecord(PARTITION, OFFSET, "topic", null, KEY_SCHEMA, KEY, RECORD_SCHEMA, RECORD)
     );
 
     @Override
@@ -98,16 +92,16 @@ public class WorkerSourceTaskTest extends ThreadedTest {
         Properties workerProps = new Properties();
         workerProps.setProperty("key.converter", "org.apache.kafka.copycat.json.JsonConverter");
         workerProps.setProperty("value.converter", "org.apache.kafka.copycat.json.JsonConverter");
-        workerProps.setProperty("key.serializer", "org.apache.kafka.copycat.json.JsonSerializer");
-        workerProps.setProperty("value.serializer", "org.apache.kafka.copycat.json.JsonSerializer");
-        workerProps.setProperty("key.deserializer", "org.apache.kafka.copycat.json.JsonDeserializer");
-        workerProps.setProperty("value.deserializer", "org.apache.kafka.copycat.json.JsonDeserializer");
+        workerProps.setProperty("offset.key.converter", "org.apache.kafka.copycat.json.JsonConverter");
+        workerProps.setProperty("offset.value.converter", "org.apache.kafka.copycat.json.JsonConverter");
+        workerProps.setProperty("offset.key.converter.schemas.enable", "false");
+        workerProps.setProperty("offset.value.converter.schemas.enable", "false");
         config = new WorkerConfig(workerProps);
         producerCallbacks = EasyMock.newCapture();
     }
 
     private void createWorkerTask() {
-        workerTask = new WorkerSourceTask<>(taskId, sourceTask, keyConverter, valueConverter, producer,
+        workerTask = new WorkerSourceTask(taskId, sourceTask, keyConverter, valueConverter, producer,
                 offsetReader, offsetWriter, config, new SystemTime());
     }
 
@@ -201,15 +195,15 @@ public class WorkerSourceTaskTest extends ThreadedTest {
 
         List<SourceRecord> records = new ArrayList<>();
         // Can just use the same record for key and value
-        records.add(new SourceRecord(PARTITION_SCHEMA, PARTITION_BYTES, OFFSET_SCHEMA, OFFSET_BYTES, "topic", null, KEY_SCHEMA, KEY, RECORD_SCHEMA, RECORD));
+        records.add(new SourceRecord(PARTITION, OFFSET, "topic", null, KEY_SCHEMA, KEY, RECORD_SCHEMA, RECORD));
 
-        Capture<ProducerRecord<ByteBuffer, String>> sent = expectSendRecord();
+        Capture<ProducerRecord<byte[], byte[]>> sent = expectSendRecord();
 
         PowerMock.replayAll();
 
         Whitebox.invokeMethod(workerTask, "sendRecords", records);
-        assertEquals(CONVERTED_KEY, sent.getValue().key());
-        assertEquals(CONVERTED_RECORD, sent.getValue().value());
+        assertEquals(SERIALIZED_KEY, sent.getValue().key());
+        assertEquals(SERIALIZED_RECORD, sent.getValue().value());
 
         PowerMock.verifyAll();
     }
@@ -233,11 +227,11 @@ public class WorkerSourceTaskTest extends ThreadedTest {
         return latch;
     }
 
-    private Capture<ProducerRecord<ByteBuffer, String>> expectSendRecord() throws InterruptedException {
-        EasyMock.expect(keyConverter.fromCopycatData(KEY_SCHEMA, KEY)).andStubReturn(CONVERTED_KEY);
-        EasyMock.expect(valueConverter.fromCopycatData(RECORD_SCHEMA, RECORD)).andStubReturn(CONVERTED_RECORD);
+    private Capture<ProducerRecord<byte[], byte[]>> expectSendRecord() throws InterruptedException {
+        EasyMock.expect(keyConverter.fromCopycatData(TOPIC, KEY_SCHEMA, KEY)).andStubReturn(SERIALIZED_KEY);
+        EasyMock.expect(valueConverter.fromCopycatData(TOPIC, RECORD_SCHEMA, RECORD)).andStubReturn(SERIALIZED_RECORD);
 
-        Capture<ProducerRecord<ByteBuffer, String>> sent = EasyMock.newCapture();
+        Capture<ProducerRecord<byte[], byte[]>> sent = EasyMock.newCapture();
         // 1. Converted data passed to the producer, which will need callbacks invoked for flush to work
         EasyMock.expect(
                 producer.send(EasyMock.capture(sent),
@@ -255,7 +249,7 @@ public class WorkerSourceTaskTest extends ThreadedTest {
                     }
                 });
         // 2. Offset data is passed to the offset storage.
-        offsetWriter.offset(new SchemaAndValue(PARTITION_SCHEMA, PARTITION_BYTES), new SchemaAndValue(OFFSET_SCHEMA, OFFSET_BYTES));
+        offsetWriter.offset(PARTITION, OFFSET);
         PowerMock.expectLastCall().anyTimes();
 
         return sent;

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerTest.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerTest.java b/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerTest.java
index 32e7ff9..701e230 100644
--- a/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerTest.java
+++ b/copycat/runtime/src/test/java/org/apache/kafka/copycat/runtime/WorkerTest.java
@@ -17,8 +17,6 @@
 
 package org.apache.kafka.copycat.runtime;
 
-import org.apache.kafka.common.serialization.Deserializer;
-import org.apache.kafka.common.serialization.Serializer;
 import org.apache.kafka.common.utils.Time;
 import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.copycat.cli.WorkerConfig;
@@ -49,10 +47,6 @@ public class WorkerTest extends ThreadedTest {
     private ConnectorTaskId taskId = new ConnectorTaskId("job", 0);
     private Worker worker;
     private OffsetBackingStore offsetBackingStore = PowerMock.createMock(OffsetBackingStore.class);
-    private Serializer offsetKeySerializer = PowerMock.createMock(Serializer.class);
-    private Serializer offsetValueSerializer = PowerMock.createMock(Serializer.class);
-    private Deserializer offsetKeyDeserializer = PowerMock.createMock(Deserializer.class);
-    private Deserializer offsetValueDeserializer = PowerMock.createMock(Deserializer.class);
 
     @Before
     public void setup() {
@@ -61,14 +55,12 @@ public class WorkerTest extends ThreadedTest {
         Properties workerProps = new Properties();
         workerProps.setProperty("key.converter", "org.apache.kafka.copycat.json.JsonConverter");
         workerProps.setProperty("value.converter", "org.apache.kafka.copycat.json.JsonConverter");
-        workerProps.setProperty("key.serializer", "org.apache.kafka.copycat.json.JsonSerializer");
-        workerProps.setProperty("value.serializer", "org.apache.kafka.copycat.json.JsonSerializer");
-        workerProps.setProperty("key.deserializer", "org.apache.kafka.copycat.json.JsonDeserializer");
-        workerProps.setProperty("value.deserializer", "org.apache.kafka.copycat.json.JsonDeserializer");
+        workerProps.setProperty("offset.key.converter", "org.apache.kafka.copycat.json.JsonConverter");
+        workerProps.setProperty("offset.value.converter", "org.apache.kafka.copycat.json.JsonConverter");
+        workerProps.setProperty("offset.key.converter.schemas.enable", "false");
+        workerProps.setProperty("offset.value.converter.schemas.enable", "false");
         WorkerConfig config = new WorkerConfig(workerProps);
-        worker = new Worker(new MockTime(), config, offsetBackingStore,
-                offsetKeySerializer, offsetValueSerializer,
-                offsetKeyDeserializer, offsetValueDeserializer);
+        worker = new Worker(new MockTime(), config, offsetBackingStore);
         worker.start();
     }
 

http://git-wip-us.apache.org/repos/asf/kafka/blob/3803e5cb/copycat/runtime/src/test/java/org/apache/kafka/copycat/storage/OffsetStorageWriterTest.java
----------------------------------------------------------------------
diff --git a/copycat/runtime/src/test/java/org/apache/kafka/copycat/storage/OffsetStorageWriterTest.java b/copycat/runtime/src/test/java/org/apache/kafka/copycat/storage/OffsetStorageWriterTest.java
index 9c0c52d..956d064 100644
--- a/copycat/runtime/src/test/java/org/apache/kafka/copycat/storage/OffsetStorageWriterTest.java
+++ b/copycat/runtime/src/test/java/org/apache/kafka/copycat/storage/OffsetStorageWriterTest.java
@@ -17,10 +17,6 @@
 
 package org.apache.kafka.copycat.storage;
 
-import org.apache.kafka.common.serialization.Serializer;
-import org.apache.kafka.copycat.data.Schema;
-import org.apache.kafka.copycat.data.SchemaAndValue;
-import org.apache.kafka.copycat.data.SchemaBuilder;
 import org.apache.kafka.copycat.errors.CopycatException;
 import org.apache.kafka.copycat.util.Callback;
 import org.easymock.Capture;
@@ -35,9 +31,7 @@ import org.powermock.api.easymock.annotation.Mock;
 import org.powermock.modules.junit4.PowerMockRunner;
 
 import java.nio.ByteBuffer;
-import java.util.Arrays;
 import java.util.Collections;
-import java.util.List;
 import java.util.Map;
 import java.util.concurrent.*;
 
@@ -48,13 +42,9 @@ import static org.junit.Assert.assertTrue;
 public class OffsetStorageWriterTest {
     private static final String NAMESPACE = "namespace";
     // Copycat format - any types should be accepted here
-    private static final Schema OFFSET_KEY_SCHEMA = SchemaBuilder.array(Schema.STRING_SCHEMA).build();
-    private static final List<String> OFFSET_KEY = Arrays.asList("key", "key");
-    private static final Schema OFFSET_VALUE_SCHEMA = Schema.STRING_SCHEMA;
-    private static final String OFFSET_VALUE = "value";
-    // Native objects - must match serializer types
-    private static final int OFFSET_KEY_CONVERTED = 12;
-    private static final String OFFSET_VALUE_CONVERTED = "value-converted";
+    private static final Map<String, String> OFFSET_KEY = Collections.singletonMap("key", "key");
+    private static final Map<String, Integer> OFFSET_VALUE = Collections.singletonMap("key", 12);
+
     // Serialized
     private static final byte[] OFFSET_KEY_SERIALIZED = "key-serialized".getBytes();
     private static final byte[] OFFSET_VALUE_SERIALIZED = "value-serialized".getBytes();
@@ -63,11 +53,9 @@ public class OffsetStorageWriterTest {
             ByteBuffer.wrap(OFFSET_VALUE_SERIALIZED));
 
     @Mock private OffsetBackingStore store;
-    @Mock private Converter<Integer> keyConverter;
-    @Mock private Converter<String> valueConverter;
-    @Mock private Serializer<Integer> keySerializer;
-    @Mock private Serializer<String> valueSerializer;
-    private OffsetStorageWriter<Integer, String> writer;
+    @Mock private Converter keyConverter;
+    @Mock private Converter valueConverter;
+    private OffsetStorageWriter writer;
 
     private static Exception exception = new RuntimeException("error");
 
@@ -75,7 +63,7 @@ public class OffsetStorageWriterTest {
 
     @Before
     public void setup() {
-        writer = new OffsetStorageWriter<>(store, NAMESPACE, keyConverter, valueConverter, keySerializer, valueSerializer);
+        writer = new OffsetStorageWriter(store, NAMESPACE, keyConverter, valueConverter);
         service = Executors.newFixedThreadPool(1);
     }
 
@@ -92,7 +80,7 @@ public class OffsetStorageWriterTest {
 
         PowerMock.replayAll();
 
-        writer.offset(new SchemaAndValue(OFFSET_KEY_SCHEMA, OFFSET_KEY), new SchemaAndValue(OFFSET_VALUE_SCHEMA, OFFSET_VALUE));
+        writer.offset(OFFSET_KEY, OFFSET_VALUE);
 
         assertTrue(writer.beginFlush());
         writer.doFlush(callback).get(1000, TimeUnit.MILLISECONDS);
@@ -128,7 +116,7 @@ public class OffsetStorageWriterTest {
 
         PowerMock.replayAll();
 
-        writer.offset(new SchemaAndValue(OFFSET_KEY_SCHEMA, OFFSET_KEY), new SchemaAndValue(OFFSET_VALUE_SCHEMA, OFFSET_VALUE));
+        writer.offset(OFFSET_KEY, OFFSET_VALUE);
         assertTrue(writer.beginFlush());
         writer.doFlush(callback).get(1000, TimeUnit.MILLISECONDS);
         assertTrue(writer.beginFlush());
@@ -148,7 +136,7 @@ public class OffsetStorageWriterTest {
 
         PowerMock.replayAll();
 
-        writer.offset(new SchemaAndValue(OFFSET_KEY_SCHEMA, OFFSET_KEY), new SchemaAndValue(OFFSET_VALUE_SCHEMA, OFFSET_VALUE));
+        writer.offset(OFFSET_KEY, OFFSET_VALUE);
         assertTrue(writer.beginFlush());
         writer.doFlush(callback);
         assertTrue(writer.beginFlush()); // should throw
@@ -160,7 +148,7 @@ public class OffsetStorageWriterTest {
     public void testCancelBeforeAwaitFlush() {
         PowerMock.replayAll();
 
-        writer.offset(new SchemaAndValue(OFFSET_KEY_SCHEMA, OFFSET_KEY), new SchemaAndValue(OFFSET_VALUE_SCHEMA, OFFSET_VALUE));
+        writer.offset(OFFSET_KEY, OFFSET_VALUE);
         assertTrue(writer.beginFlush());
         writer.cancelFlush();
 
@@ -178,7 +166,7 @@ public class OffsetStorageWriterTest {
 
         PowerMock.replayAll();
 
-        writer.offset(new SchemaAndValue(OFFSET_KEY_SCHEMA, OFFSET_KEY), new SchemaAndValue(OFFSET_VALUE_SCHEMA, OFFSET_VALUE));
+        writer.offset(OFFSET_KEY, OFFSET_VALUE);
         assertTrue(writer.beginFlush());
         // Start the flush, then immediately cancel before allowing the mocked store request to finish
         Future<Void> flushFuture = writer.doFlush(callback);
@@ -207,10 +195,8 @@ public class OffsetStorageWriterTest {
     private void expectStore(final Callback<Void> callback,
                              final boolean fail,
                              final CountDownLatch waitForCompletion) {
-        EasyMock.expect(keyConverter.fromCopycatData(OFFSET_KEY_SCHEMA, OFFSET_KEY)).andReturn(OFFSET_KEY_CONVERTED);
-        EasyMock.expect(keySerializer.serialize(NAMESPACE, OFFSET_KEY_CONVERTED)).andReturn(OFFSET_KEY_SERIALIZED);
-        EasyMock.expect(valueConverter.fromCopycatData(OFFSET_VALUE_SCHEMA, OFFSET_VALUE)).andReturn(OFFSET_VALUE_CONVERTED);
-        EasyMock.expect(valueSerializer.serialize(NAMESPACE, OFFSET_VALUE_CONVERTED)).andReturn(OFFSET_VALUE_SERIALIZED);
+        EasyMock.expect(keyConverter.fromCopycatData(NAMESPACE, null, OFFSET_KEY)).andReturn(OFFSET_KEY_SERIALIZED);
+        EasyMock.expect(valueConverter.fromCopycatData(NAMESPACE, null, OFFSET_VALUE)).andReturn(OFFSET_VALUE_SERIALIZED);
 
         final Capture<Callback<Void>> storeCallback = Capture.newInstance();
         EasyMock.expect(store.set(EasyMock.eq(NAMESPACE), EasyMock.eq(OFFSETS_SERIALIZED),