001 /* 002 * Copyright (c) 2007-2014 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 */ 020 021 package cascading.flow.stream; 022 023 import java.util.ArrayList; 024 import java.util.Arrays; 025 import java.util.Collection; 026 import java.util.Collections; 027 import java.util.concurrent.CountDownLatch; 028 029 import cascading.flow.FlowProcess; 030 import cascading.pipe.HashJoin; 031 import cascading.tuple.Tuple; 032 import cascading.tuple.TupleEntry; 033 import org.slf4j.Logger; 034 import org.slf4j.LoggerFactory; 035 036 /** 037 * 038 */ 039 public class MemoryHashJoinGate extends MemorySpliceGate 040 { 041 private static final Logger LOG = LoggerFactory.getLogger( MemoryHashJoinGate.class ); 042 043 protected CountDownLatch latch; 044 045 private Collection<Tuple>[] collections; 046 private ArrayList<Tuple> streamedCollection; 047 048 public MemoryHashJoinGate( FlowProcess flowProcess, HashJoin join ) 049 { 050 super( flowProcess, join ); 051 } 052 053 @Override 054 public void bind( StreamGraph streamGraph ) 055 { 056 super.bind( streamGraph ); 057 058 count.set( numIncomingPaths ); // the number of paths incoming 059 latch = new CountDownLatch( numIncomingPaths - 1 ); 060 } 061 062 @Override 063 public void prepare() 064 { 065 super.prepare(); 066 067 streamedCollection = new ArrayList<Tuple>( Arrays.asList( new Tuple() ) ); // placeholder in collection 068 collections = new Collection[ orderedPrevious.length ]; 069 collections[ 0 ] = streamedCollection; 070 071 if( nullsAreNotEqual ) 072 LOG.warn( "HashJoin does not fully support key comparators where null values are not treated equal" ); 073 } 074 075 @Override 076 public void receive( Duct previous, TupleEntry incomingEntry ) 077 { 078 int pos = posMap.get( previous ); 079 080 Tuple incomingTuple = pos != 0 ? incomingEntry.getTupleCopy() : incomingEntry.getTuple(); 081 Tuple keyTuple = keyBuilder[ pos ].makeResult( incomingTuple, null ); // view in incomingTuple 082 083 keyTuple = getDelegatedTuple( keyTuple ); 084 085 if( pos != 0 ) 086 { 087 keys.add( keyTuple ); 088 keyValues[ pos ].get( keyTuple ).add( incomingTuple ); // always a copy 089 return; 090 } 091 092 waitOnLatch(); 093 094 keys.remove( keyTuple ); 095 096 streamedCollection.set( 0, incomingTuple ); // no need to copy, temp setting 097 098 performJoinWith( keyTuple ); 099 } 100 101 private void performJoinWith( Tuple keyTuple ) 102 { 103 // never replace the first array, pos == 0 104 for( int i = 1; i < keyValues.length; i++ ) 105 { 106 // if key does not exist, #get will create an empty array list, 107 // and store the key, which is not a copy 108 if( keyValues[ i ].containsKey( keyTuple ) ) 109 collections[ i ] = keyValues[ i ].get( keyTuple ); 110 else 111 collections[ i ] = Collections.EMPTY_LIST; 112 } 113 114 closure.reset( collections ); 115 116 keyEntry.setTuple( keyTuple ); 117 tupleEntryIterator.reset( splice.getJoiner().getIterator( closure ) ); 118 119 next.receive( this, grouping ); 120 } 121 122 @Override 123 public void complete( Duct previous ) 124 { 125 countDownLatch(); 126 127 if( count.decrementAndGet() != 0 ) 128 return; 129 130 collections[ 0 ] = Collections.EMPTY_LIST; 131 132 for( Tuple keyTuple : keys ) 133 performJoinWith( keyTuple ); 134 135 keys = createKeySet(); 136 keyValues = createKeyValuesArray(); 137 138 super.complete( previous ); 139 } 140 141 protected void waitOnLatch() 142 { 143 try 144 { 145 latch.await(); 146 } 147 catch( InterruptedException exception ) 148 { 149 throw new RuntimeException( "interrupted", exception ); 150 } 151 } 152 153 protected void countDownLatch() 154 { 155 latch.countDown(); 156 } 157 158 @Override 159 protected boolean isBlockingStreamed() 160 { 161 return false; 162 } 163 }