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.aggregates.collections;
  
  import java.io.IOException;
  
  import org.apache.asterix.builders.OrderedListBuilder;
  import org.apache.asterix.om.types.AOrderedListType;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.asterix.om.types.TypeHelper;
  import org.apache.asterix.runtime.aggregates.std.AbstractAggregateFunction;
  import org.apache.asterix.runtime.evaluators.functions.CastTypeEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IAggregateEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IAggregateEvaluatorFactory;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.exceptions.SourceLocation;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  public class ListifyAggregateFunctionEvalFactory implements IAggregateEvaluatorFactory {
  
      private static final long serialVersionUID = 1L;
      private IScalarEvaluatorFactory[] args;
      private final AOrderedListType orderedListType;
      private final IAType itemType;
      private final SourceLocation sourceLoc;
  
      ListifyAggregateFunctionEvalFactory(IScalarEvaluatorFactory[] args, AOrderedListType type, IAType itemType,
              SourceLocation sourceLoc) {
          this.args = args;
          this.orderedListType = type;
          this.itemType = itemType;
          this.sourceLoc = sourceLoc;
      }
  
      @Override
      public IAggregateEvaluator createAggregateEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
          return new AbstractAggregateFunction(sourceLoc) {
  
              private IPointable inputVal = new VoidPointable();
              private IScalarEvaluator eval = args[0].createScalarEvaluator(ctx);
              private ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
              private OrderedListBuilder builder = new OrderedListBuilder();
              // create caster to open up input item if the list item type is ANY but the received item is not fully open
              private final CastTypeEvaluator caster =
                      orderedListType.getItemType().getTypeTag() == ATypeTag.ANY && !TypeHelper.isFullyOpen(itemType)
                              ? new CastTypeEvaluator(BuiltinType.ANY, itemType, eval, sourceLoc) : null;
  
              @Override
              public void init() throws HyracksDataException {
                  builder.reset(orderedListType);
              }
  
              @Override
              public void step(IFrameTupleReference tuple) throws HyracksDataException {
                  try {
                      if (caster != null) {
                          caster.evaluate(tuple, inputVal);
                      } else {
                          eval.evaluate(tuple, inputVal);
                      }
                      builder.addItem(inputVal);
                  } catch (IOException e) {
                      throw HyracksDataException.create(e);
                  }
              }
  
              @Override
              public void finish(IPointable result) throws HyracksDataException {
                  resultStorage.reset();
                  try {
                      builder.write(resultStorage.getDataOutput(), true);
                  } catch (IOException e) {
                      throw HyracksDataException.create(e);
                  }
                  result.set(resultStorage);
              }
  
              @Override
              public void finishPartial(IPointable result) throws HyracksDataException {
                  finish(result);
              }
  
          };
      }
  
  }
  