content: /*
   * 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.asterix.runtime.evaluators.functions.records;
  
  import java.io.DataOutput;
  import java.io.IOException;
  import java.util.List;
  
  import org.apache.asterix.builders.OrderedListBuilder;
  import org.apache.asterix.builders.RecordBuilder;
  import org.apache.asterix.dataflow.data.nontagged.serde.AObjectSerializerDeserializer;
  import org.apache.asterix.om.base.AString;
  import org.apache.asterix.om.pointables.ARecordVisitablePointable;
  import org.apache.asterix.om.pointables.base.DefaultOpenFieldType;
  import org.apache.asterix.om.pointables.base.IVisitablePointable;
  import org.apache.asterix.om.types.AOrderedListType;
  import org.apache.asterix.om.types.ARecordType;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  
  class RecordPairsEvaluator extends AbstractRecordPairsEvaluator {
  
      // For writing output list
      private final OrderedListBuilder listBuilder = new OrderedListBuilder();
  
      // For writing each individual output record.
      private final ArrayBackedValueStorage itemStorage = new ArrayBackedValueStorage();
      private final DataOutput itemOutput = itemStorage.getDataOutput();
      private final RecordBuilder recBuilder = new RecordBuilder();
  
      // Sets up the constant field names, "name" for the key field, "value" for the value field.
      private final ArrayBackedValueStorage nameStorage = new ArrayBackedValueStorage();
      private final ArrayBackedValueStorage valueStorage = new ArrayBackedValueStorage();
  
      private ARecordVisitablePointable recordVisitablePointable;
  
      RecordPairsEvaluator(IScalarEvaluator eval0, ARecordType recordType) throws HyracksDataException {
          super(eval0, recordType);
          recBuilder.reset(DefaultOpenFieldType.NESTED_OPEN_RECORD_TYPE);
          recordVisitablePointable = new ARecordVisitablePointable(DefaultOpenFieldType.NESTED_OPEN_RECORD_TYPE);
  
          try {
              AObjectSerializerDeserializer serde = AObjectSerializerDeserializer.INSTANCE;
              serde.serialize(new AString("name"), nameStorage.getDataOutput());
              serde.serialize(new AString("value"), valueStorage.getDataOutput());
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
      }
  
      @Override
      protected void buildOutput() throws HyracksDataException {
          listBuilder.reset(AOrderedListType.FULL_OPEN_ORDEREDLIST_TYPE);
  
          recordVisitablePointable.set(inputPointable);
          List<IVisitablePointable> fieldNames = recordVisitablePointable.getFieldNames();
          List<IVisitablePointable> fieldValues = recordVisitablePointable.getFieldValues();
          // Adds each field of the input record as a key-value pair into the result.
          int numFields = recordVisitablePointable.getFieldNames().size();
          for (int fieldIndex = 0; fieldIndex < numFields; ++fieldIndex) {
              itemStorage.reset();
              recBuilder.init();
              recBuilder.addField(nameStorage, fieldNames.get(fieldIndex));
              recBuilder.addField(valueStorage, fieldValues.get(fieldIndex));
              recBuilder.write(itemOutput, true);
              listBuilder.addItem(itemStorage);
          }
  
          // Writes the result and sets the result pointable.
          listBuilder.write(resultOutput, true);
      }
  
      @Override
      protected boolean validateInputType(ATypeTag inputTypeTag) {
          return inputTypeTag == ATypeTag.OBJECT;
      }
  }
  