/*
* Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
*
* Project and contact information: http://www.cascading.org/
*
* This file is part of the Cascading project.
*
* Licensed 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 cascading.flow.tez;
import java.util.Collection;
import java.util.Iterator;
import cascading.flow.FlowProcess;
import cascading.flow.hadoop.HadoopCoGroupClosure;
import cascading.flow.hadoop.util.LazySpillableTupleCollection;
import cascading.flow.hadoop.util.ResettableCollection;
import cascading.tuple.Fields;
import cascading.tuple.Tuple;
/**
*
*/
public class TezCoGroupClosure extends HadoopCoGroupClosure
{
public TezCoGroupClosure( FlowProcess flowProcess, int numSelfJoins, Fields[] groupingFields, Fields[] valueFields )
{
super( flowProcess, numSelfJoins, groupingFields, valueFields );
}
protected void build()
{
clearGroups();
for( int pos = 0; pos < values.length; pos++ )
( (ResettableCollection) collections[ pos ] ).reset( values[ pos ] );
// todo: prevent an initial iteration to populate the lazy collection
if( numSelfJoins != 0 ) // force fill of lazy collection
{
Iterator<Tuple> iterator = collections[ 0 ].iterator();
while( iterator.hasNext() )
iterator.next(); // do nothing, populates the lazy collection
}
}
@Override
protected Collection<Tuple> createTupleCollection( Fields joinField )
{
return new LazySpillableTupleCollection( super.createTupleCollection( joinField ) );
}
}