    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.graph;
    023
    024import cascading.flow.FlowElement;
    025import cascading.flow.FlowNode;
    026import cascading.flow.hadoop.HadoopFlowProcess;
    027import cascading.flow.hadoop.stream.element.HadoopCoGroupGate;
    028import cascading.flow.hadoop.stream.element.HadoopGroupByGate;
    029import cascading.flow.hadoop.stream.element.HadoopSinkStage;
    030import cascading.flow.stream.duct.Duct;
    031import cascading.flow.stream.duct.Gate;
    032import cascading.flow.stream.element.SinkStage;
    033import cascading.flow.stream.graph.IORole;
    034import cascading.flow.stream.graph.NodeStreamGraph;
    035import cascading.pipe.CoGroup;
    036import cascading.pipe.Group;
    037import cascading.pipe.GroupBy;
    038import cascading.pipe.HashJoin;
    039import cascading.tap.Tap;
    040import cascading.util.Util;
    041
    042/**
    043 *
    044 */
    045public class HadoopReduceStreamGraph extends NodeStreamGraph
    046  {
    047  public HadoopReduceStreamGraph( HadoopFlowProcess flowProcess, FlowNode node, FlowElement sourceElement )
    048    {
    049    super( flowProcess, node, sourceElement );
    050
    051    buildGraph();
    052
    053    setTraps();
    054    setScopes();
    055
    056    printGraph( node.getID(), "reduce", flowProcess.getCurrentSliceNum() );
    057
    058    bind();
    059
    060    printBoundGraph( node.getID(), "reduce", flowProcess.getCurrentSliceNum() );
    061    }
    062
    063  protected void buildGraph()
    064    {
    065    Group group = (Group) Util.getFirst( node.getSourceElements() );
    066
    067    Duct rhsDuct;
    068
    069    if( group.isGroupBy() )
    070      rhsDuct = new HadoopGroupByGate( flowProcess, (GroupBy) group, IORole.source );
    071    else
    072      rhsDuct = new HadoopCoGroupGate( flowProcess, (CoGroup) group, IORole.source );
    073
    074    addHead( rhsDuct );
    075
    076    handleDuct( group, rhsDuct );
    077    }
    078
    079  @Override
    080  protected SinkStage createSinkStage( Tap element )
    081    {
    082    return new HadoopSinkStage( flowProcess, element );
    083    }
    084
    085  protected Gate createCoGroupGate( CoGroup element, IORole role )
    086    {
    087    throw new IllegalStateException( "should not happen" );
    088    }
    089
    090  @Override
    091  protected Gate createGroupByGate( GroupBy element, IORole role )
    092    {
    093    throw new IllegalStateException( "should not happen" );
    094    }
    095
    096  @Override
    097  protected Gate createHashJoinGate( HashJoin join )
    098    {
    099    throw new IllegalStateException( "should not happen" );
    100    }
    101
    102  }