/*
* 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.tuple.hadoop.util;
import java.io.InputStream;
import java.util.Comparator;
import cascading.CascadingException;
import cascading.tuple.StreamComparator;
import cascading.tuple.hadoop.io.HadoopTupleInputStream;
import cascading.tuple.hadoop.io.HadoopTupleOutputStream;
/**
*
*/
public class TupleElementStreamComparator implements StreamComparator<HadoopTupleInputStream>, Comparator<Object>
{
final StreamComparator comparator;
public TupleElementStreamComparator( StreamComparator comparator )
{
this.comparator = comparator;
}
@Override
public int compare( Object lhs, Object rhs )
{
return ( (Comparator<Object>) comparator ).compare( lhs, rhs );
}
@Override
public int compare( HadoopTupleInputStream lhsStream, HadoopTupleInputStream rhsStream )
{
try
{
// pop off element type, its assumed we know it as we have a stream comparator
// to delegate too
int lhsToken = lhsStream.readToken();
int rhsToken = rhsStream.readToken();
if( lhsToken == HadoopTupleOutputStream.WRITABLE_TOKEN )
lhsStream.readString();
if( rhsToken == HadoopTupleOutputStream.WRITABLE_TOKEN )
rhsStream.readString();
InputStream lhs = lhsToken == 0 ? null : lhsStream.getInputStream();
InputStream rhs = rhsToken == 0 ? null : rhsStream.getInputStream();
return comparator.compare( lhs, rhs );
}
catch( Exception exception )
{
throw new CascadingException( "unable to compare Tuples, likely a CoGroup is being attempted on fields of " +
"different types or custom comparators are incorrectly set on Fields", exception );
}
}
}