[flink] branch master updated: [FLINK-12253][table-common] Add a MULTISET type

[tw...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

twalthr pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/flink.git


The following commit(s) were added to refs/heads/master by this push:
     new 8e8eb35  [FLINK-12253][table-common] Add a MULTISET type
8e8eb35 is described below

commit 8e8eb357b387f090ea2c44965b60e7922a98e5ad
Author: Timo Walther <tw...@apache.org>
AuthorDate: Thu May 2 11:35:29 2019 +0200

    [FLINK-12253][table-common] Add a MULTISET type
---
 .../table/types/logical/LogicalTypeVisitor.java    |   2 +
 .../flink/table/types/logical/MultisetType.java    | 127 +++++++++++++++++++++
 .../apache/flink/table/types/LogicalTypesTest.java |  25 ++++
 3 files changed, 154 insertions(+)

diff --git a/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/LogicalTypeVisitor.java b/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/LogicalTypeVisitor.java
index 877007b..33a496a 100644
--- a/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/LogicalTypeVisitor.java
+++ b/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/LogicalTypeVisitor.java
@@ -69,5 +69,7 @@ public interface LogicalTypeVisitor<R> {
 
 	R visit(ArrayType arrayType);
 
+	R visit(MultisetType multisetType);
+
 	R visit(LogicalType other);
 }
diff --git a/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/MultisetType.java b/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/MultisetType.java
new file mode 100644
index 0000000..c093306
--- /dev/null
+++ b/flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/MultisetType.java
@@ -0,0 +1,127 @@
+/*
+ * 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.flink.table.types.logical;
+
+import org.apache.flink.annotation.PublicEvolving;
+import org.apache.flink.util.Preconditions;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Logical type of a multiset (=bag). Unlike a set, it allows for multiple instances for each of its
+ * elements with a common subtype. Each unique value (including {@code NULL}) is mapped to some
+ * multiplicity. There is no restriction of element types; it is the responsibility of the user to
+ * ensure uniqueness.
+ *
+ * <p>The serialized string representation is {@code MULTISET<t>} where {@code t} is the logical type
+ * of the contained elements.
+ *
+ * <p>A conversion is possible through a map that assigns each value to an integer multiplicity
+ * ({@code Map<t, Integer>}).
+ */
+@PublicEvolving
+public final class MultisetType extends LogicalType {
+
+	private static final String FORMAT = "MULTISET<%s>";
+
+	private static final Set<String> INPUT_OUTPUT_CONVERSION = conversionSet(
+		Map.class.getName(),
+		"org.apache.flink.table.dataformat.BinaryMap");
+
+	private static final Class<?> DEFAULT_CONVERSION = Map.class;
+
+	private final LogicalType elementType;
+
+	public MultisetType(boolean isNullable, LogicalType elementType) {
+		super(isNullable, LogicalTypeRoot.MULTISET);
+		this.elementType = Preconditions.checkNotNull(elementType, "Element type must not be null.");
+	}
+
+	public MultisetType(LogicalType elementType) {
+		this(true, elementType);
+	}
+
+	public LogicalType getElementType() {
+		return elementType;
+	}
+
+	@Override
+	public LogicalType copy(boolean isNullable) {
+		return new MultisetType(isNullable, elementType.copy());
+	}
+
+	@Override
+	public String asSummaryString() {
+		return withNullability(FORMAT, elementType.asSummaryString());
+	}
+
+	@Override
+	public String asSerializableString() {
+		return withNullability(FORMAT, elementType.asSerializableString());
+	}
+
+	@Override
+	public boolean supportsInputConversion(Class<?> clazz) {
+		return INPUT_OUTPUT_CONVERSION.contains(clazz.getName());
+	}
+
+	@Override
+	public boolean supportsOutputConversion(Class<?> clazz) {
+		return INPUT_OUTPUT_CONVERSION.contains(clazz.getName());
+	}
+
+	@Override
+	public Class<?> getDefaultConversion() {
+		return DEFAULT_CONVERSION;
+	}
+
+	@Override
+	public List<LogicalType> getChildren() {
+		return Collections.singletonList(elementType);
+	}
+
+	@Override
+	public <R> R accept(LogicalTypeVisitor<R> visitor) {
+		return visitor.visit(this);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (o == null || getClass() != o.getClass()) {
+			return false;
+		}
+		if (!super.equals(o)) {
+			return false;
+		}
+		MultisetType that = (MultisetType) o;
+		return elementType.equals(that.elementType);
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(super.hashCode(), elementType);
+	}
+}
diff --git a/flink-table/flink-table-common/src/test/java/org/apache/flink/table/types/LogicalTypesTest.java b/flink-table/flink-table-common/src/test/java/org/apache/flink/table/types/LogicalTypesTest.java
index e701da6..1e621d7 100644
--- a/flink-table/flink-table-common/src/test/java/org/apache/flink/table/types/LogicalTypesTest.java
+++ b/flink-table/flink-table-common/src/test/java/org/apache/flink/table/types/LogicalTypesTest.java
@@ -31,6 +31,7 @@ import org.apache.flink.table.types.logical.FloatType;
 import org.apache.flink.table.types.logical.IntType;
 import org.apache.flink.table.types.logical.LocalZonedTimestampType;
 import org.apache.flink.table.types.logical.LogicalType;
+import org.apache.flink.table.types.logical.MultisetType;
 import org.apache.flink.table.types.logical.SmallIntType;
 import org.apache.flink.table.types.logical.TimeType;
 import org.apache.flink.table.types.logical.TimestampType;
@@ -46,6 +47,7 @@ import org.junit.Test;
 
 import java.math.BigDecimal;
 import java.util.Arrays;
+import java.util.Map;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -331,6 +333,29 @@ public class LogicalTypesTest {
 		assertFalse(nestedArray.supportsOutputConversion(java.sql.Timestamp[].class));
 	}
 
+	@Test
+	public void testMultisetType() {
+		testAll(
+			new MultisetType(new TimestampType()),
+			"MULTISET<TIMESTAMP(6)>",
+			"MULTISET<TIMESTAMP(6)>",
+			new Class[]{Map.class},
+			new Class[]{Map.class},
+			new LogicalType[]{new TimestampType()},
+			new MultisetType(new SmallIntType())
+		);
+
+		testAll(
+			new MultisetType(new MultisetType(new TimestampType())),
+			"MULTISET<MULTISET<TIMESTAMP(6)>>",
+			"MULTISET<MULTISET<TIMESTAMP(6)>>",
+			new Class[]{Map.class},
+			new Class[]{Map.class},
+			new LogicalType[]{new MultisetType(new TimestampType())},
+			new MultisetType(new MultisetType(new SmallIntType()))
+		);
+	}
+
 	// --------------------------------------------------------------------------------------------
 
 	private static void testAll(