/*
* 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.hadoop;
import java.util.Iterator;
import cascading.flow.FlowProcess;
import cascading.pipe.joiner.JoinerClosure;
import cascading.tuple.Fields;
import cascading.tuple.Tuple;
import cascading.tuple.util.TupleBuilder;
import cascading.tuple.util.TupleViews;
/** Class GroupClosure is used internally to represent groups of tuples during grouping. */
public class HadoopGroupByClosure extends JoinerClosure
{
protected Tuple grouping;
protected Iterator[] values;
public HadoopGroupByClosure( FlowProcess flowProcess, Fields[] groupingFields, Fields[] valueFields )
{
super( flowProcess, groupingFields, valueFields );
}
public Tuple getGrouping()
{
return grouping;
}
public int size()
{
return 1;
}
protected Iterator getValueIterator( int pos )
{
return values[ pos ];
}
@Override
public Iterator<Tuple> getIterator( int pos )
{
if( pos != 0 )
throw new IllegalArgumentException( "invalid group position: " + pos );
return makeIterator( 0, getValueIterator( 0 ) );
}
@Override
public boolean isEmpty( int pos )
{
return values != null;
}
protected Iterator<Tuple> makeIterator( final int pos, final Iterator values )
{
return new Iterator<Tuple>()
{
final int cleanPos = valueFields.length == 1 ? 0 : pos; // support repeated pipes
TupleBuilder[] valueBuilder = new TupleBuilder[ valueFields.length ];
{
for( int i = 0; i < valueFields.length; i++ )
valueBuilder[ i ] = makeBuilder( valueFields[ i ], joinFields[ i ] );
}
private TupleBuilder makeBuilder( final Fields valueField, final Fields joinField )
{
if( valueField.isUnknown() || joinField.isNone() )
return new TupleBuilder()
{
@Override
public Tuple makeResult( Tuple valueTuple, Tuple groupTuple )
{
valueTuple.set( valueFields[ cleanPos ], joinFields[ cleanPos ], groupTuple );
return valueTuple;
}
};
return new TupleBuilder()
{
Tuple result = TupleViews.createOverride( valueField, joinField );
@Override
public Tuple makeResult( Tuple valueTuple, Tuple groupTuple )
{
return TupleViews.reset( result, valueTuple, groupTuple );
}
};
}
public boolean hasNext()
{
return values.hasNext();
}
public Tuple next()
{
Tuple tuple = (Tuple) values.next();
return valueBuilder[ cleanPos ].makeResult( tuple, grouping );
}
public void remove()
{
throw new UnsupportedOperationException( "remove not supported" );
}
};
}
public void reset( Tuple grouping, Iterator<Tuple>... values )
{
this.grouping = grouping;
this.values = values;
}
@Override
public Tuple getGroupTuple( Tuple keysTuple )
{
return keysTuple;
}
}