[GitHub] [drill] paul-rogers commented on a change in pull request #2068: DRILL-7717: Support Mongo extended types in V2 JSON loader

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paul-rogers commented on a change in pull request #2068:
URL: https://github.com/apache/drill/pull/2068#discussion_r419145721



##########
File path: exec/java-exec/src/main/java/org/apache/drill/exec/store/easy/json/extended/ExtendedTypeFieldFactory.java
##########
@@ -0,0 +1,207 @@
+/*
+ * 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.drill.exec.store.easy.json.extended;
+
+import org.apache.drill.common.types.TypeProtos.MinorType;
+import org.apache.drill.exec.record.metadata.MetadataUtils;
+import org.apache.drill.exec.store.easy.json.loader.BaseFieldFactory;
+import org.apache.drill.exec.store.easy.json.loader.FieldDefn;
+import org.apache.drill.exec.store.easy.json.loader.FieldFactory;
+import org.apache.drill.exec.store.easy.json.loader.JsonLoaderImpl;
+import org.apache.drill.exec.store.easy.json.parser.ElementParser;
+import org.apache.drill.exec.store.easy.json.parser.TokenIterator;
+import org.apache.drill.exec.store.easy.json.parser.ValueParser;
+import org.apache.drill.exec.store.easy.json.values.BinaryValueListener;
+import org.apache.drill.exec.store.easy.json.values.UtcDateValueListener;
+import org.apache.drill.exec.store.easy.json.values.DecimalValueListener;
+import org.apache.drill.exec.store.easy.json.values.IntervalValueListener;
+import org.apache.drill.exec.store.easy.json.values.StrictBigIntValueListener;
+import org.apache.drill.exec.store.easy.json.values.StrictDoubleValueListener;
+import org.apache.drill.exec.store.easy.json.values.StrictIntValueListener;
+import org.apache.drill.exec.store.easy.json.values.StrictStringValueListener;
+import org.apache.drill.exec.store.easy.json.values.TimeValueListener;
+import org.apache.drill.exec.store.easy.json.values.UtcTimestampValueListener;
+
+import com.fasterxml.jackson.core.JsonToken;
+
+public class ExtendedTypeFieldFactory extends BaseFieldFactory {
+
+  public ExtendedTypeFieldFactory(JsonLoaderImpl loader, FieldFactory child) {
+    super(loader, child);
+  }
+
+  @Override
+  public ElementParser fieldParser(FieldDefn fieldDefn) {
+    ElementParser parser = buildExtendedTypeParser(fieldDefn);
+    if (parser == null) {
+      return child.fieldParser(fieldDefn);
+    } else {
+      return parser;
+    }
+  }
+
+  private ElementParser buildExtendedTypeParser(FieldDefn fieldDefn) {
+
+    // Extended types are objects: { "$type": ... }
+    // Extended arrays are [ { "$type": ...
+    TokenIterator tokenizer = fieldDefn.tokenizer();
+    JsonToken token = tokenizer.requireNext();
+    ElementParser parser;
+    switch (token) {
+      case START_OBJECT:
+        parser = extendedTypeParserFor(fieldDefn, false);
+        break;
+      case START_ARRAY:
+        parser = arrayParserFor(fieldDefn);
+        break;
+      default:
+        parser = null;
+    }
+    tokenizer.unget(token);
+    return parser;
+  }
+
+  private ElementParser arrayParserFor(FieldDefn fieldDefn) {
+    TokenIterator tokenizer = fieldDefn.tokenizer();
+    JsonToken token = tokenizer.requireNext();
+    if (token != JsonToken.START_OBJECT) {
+      tokenizer.unget(token);
+      return null;
+    }
+
+    ValueParser element = extendedTypeParserFor(fieldDefn, true);
+    tokenizer.unget(token);
+    if (element == null) {
+      return null;
+    }
+
+    return scalarArrayParserFor(element);
+  }
+
+  private BaseExtendedValueParser extendedTypeParserFor(FieldDefn fieldDefn, boolean isArray) {
+    TokenIterator tokenizer = fieldDefn.tokenizer();
+    JsonToken token = tokenizer.peek();
+    if (token != JsonToken.FIELD_NAME) {
+      return null;
+    }
+
+    String key = tokenizer.textValue().trim();
+    if (!key.startsWith(ExtendedTypeNames.TYPE_PREFIX)) {
+      return null;
+    }
+    return parserFor(fieldDefn, key, isArray);
+  }
+
+  private BaseExtendedValueParser parserFor(FieldDefn fieldDefn, String key, boolean isArray) {
+    switch (key) {
+    case ExtendedTypeNames.LONG:
+      return numberLongParser(fieldDefn, isArray);
+    case ExtendedTypeNames.DECIMAL:
+      return numberDecimalParser(fieldDefn, isArray);
+    case ExtendedTypeNames.DOUBLE:
+      return numberDoubleParser(fieldDefn, isArray);
+    case ExtendedTypeNames.INT:
+      return numberIntParser(fieldDefn, isArray);
+    case ExtendedTypeNames.DATE:
+      return dateParser(fieldDefn, isArray);
+    case ExtendedTypeNames.BINARY:
+    case ExtendedTypeNames.BINARY_TYPE:
+      return binaryParser(fieldDefn, isArray);
+    case ExtendedTypeNames.OBJECT_ID:
+      return oidParser(fieldDefn, isArray);
+    case ExtendedTypeNames.DATE_DAY:
+      return dateDayParser(fieldDefn, isArray);
+    case ExtendedTypeNames.TIME:
+      return timeParser(fieldDefn, isArray);
+    case ExtendedTypeNames.INTERVAL:
+      return intervalParser(fieldDefn, isArray);
+    default:
+      return null;
+    }
+  }
+
+  private BaseExtendedValueParser numberLongParser(FieldDefn fieldDefn, boolean isArray) {
+    return new SimpleExtendedValueParser(
+        fieldDefn.parser(), ExtendedTypeNames.LONG,
+        new StrictBigIntValueListener(loader(),
+            fieldDefn.scalarWriterFor(MinorType.BIGINT, isArray)));
+  }
+
+  private BaseExtendedValueParser numberDecimalParser(FieldDefn fieldDefn, boolean isArray) {
+    // No information about precision and scale, so guess (38, 10).

Review comment:
       Thank you for the reminder. Yes, I had planned to combine provided schema support with extended types. Now added and a test shows that `VARDECIMAL` now works as you requested.




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