    001/*
    002 * Copyright (c) 2016 Chris K Wensel <chris@wensel.net>. All Rights Reserved.
    003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
    004 *
    005 * Project and contact information: http://www.cascading.org/
    006 *
    007 * This file is part of the Cascading project.
    008 *
    009 * Licensed under the Apache License, Version 2.0 (the "License");
    010 * you may not use this file except in compliance with the License.
    011 * You may obtain a copy of the License at
    012 *
    013 *     http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing, software
    016 * distributed under the License is distributed on an "AS IS" BASIS,
    017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    018 * See the License for the specific language governing permissions and
    019 * limitations under the License.
    020 */
    021
    022package cascading.flow.hadoop.stream.element;
    023
    024import cascading.flow.FlowProcess;
    025import cascading.flow.hadoop.HadoopFlowProcess;
    026import cascading.flow.hadoop.HadoopGroupByClosure;
    027import cascading.flow.hadoop.stream.HadoopGroupGate;
    028import cascading.flow.stream.duct.Duct;
    029import cascading.flow.stream.graph.IORole;
    030import cascading.pipe.GroupBy;
    031import cascading.tuple.Tuple;
    032import cascading.tuple.io.TuplePair;
    033import org.apache.hadoop.mapred.OutputCollector;
    034
    035/**
    036 *
    037 */
    038public class HadoopGroupByGate extends HadoopGroupGate
    039  {
    040  public HadoopGroupByGate( FlowProcess flowProcess, GroupBy groupBy, IORole role )
    041    {
    042    super( flowProcess, groupBy, role );
    043    }
    044
    045  @Override
    046  protected HadoopGroupByClosure createClosure()
    047    {
    048    // todo: collapse keyFields here if an array size > 1
    049    return new HadoopGroupByClosure( flowProcess, keyFields, valuesFields );
    050    }
    051
    052  @Override
    053  protected void wrapGroupingAndCollect( Duct previous, int ordinal, Tuple valuesTuple, Tuple groupKey ) throws java.io.IOException
    054    {
    055    collector.collect( groupKey, valuesTuple );
    056    }
    057
    058  @Override
    059  protected Tuple unwrapGrouping( Tuple key )
    060    {
    061    return sortFields == null ? key : ( (TuplePair) key ).getLhs();
    062    }
    063
    064  protected OutputCollector createOutputCollector()
    065    {
    066    return ( (HadoopFlowProcess) flowProcess ).getOutputCollector();
    067    }
    068  }