001/* 002 * Copyright (c) 2007-2015 Concurrent, Inc. All Rights Reserved. 003 * 004 * Project and contact information: http://www.cascading.org/ 005 * 006 * This file is part of the Cascading project. 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020 021package cascading.flow.hadoop.stream.element; 022 023import cascading.flow.FlowProcess; 024import cascading.flow.hadoop.HadoopFlowProcess; 025import cascading.flow.hadoop.HadoopGroupByClosure; 026import cascading.flow.hadoop.stream.HadoopGroupGate; 027import cascading.flow.stream.duct.Duct; 028import cascading.flow.stream.graph.IORole; 029import cascading.pipe.GroupBy; 030import cascading.tuple.Tuple; 031import cascading.tuple.io.TuplePair; 032import org.apache.hadoop.mapred.OutputCollector; 033 034/** 035 * 036 */ 037public class HadoopGroupByGate extends HadoopGroupGate 038 { 039 public HadoopGroupByGate( FlowProcess flowProcess, GroupBy groupBy, IORole role ) 040 { 041 super( flowProcess, groupBy, role ); 042 } 043 044 @Override 045 protected HadoopGroupByClosure createClosure() 046 { 047 // todo: collapse keyFields here if an array size > 1 048 return new HadoopGroupByClosure( flowProcess, keyFields, valuesFields ); 049 } 050 051 @Override 052 protected void wrapGroupingAndCollect( Duct previous, Tuple valuesTuple, Tuple groupKey ) throws java.io.IOException 053 { 054 collector.collect( groupKey, valuesTuple ); 055 } 056 057 @Override 058 protected Tuple unwrapGrouping( Tuple key ) 059 { 060 return sortFields == null ? key : ( (TuplePair) key ).getLhs(); 061 } 062 063 protected OutputCollector createOutputCollector() 064 { 065 return ( (HadoopFlowProcess) flowProcess ).getOutputCollector(); 066 } 067 }