001/*
002 * Copyright (c) 2007-2017 Xplenty, 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.tuple.hadoop.util;
022
023import java.io.IOException;
024
025import cascading.CascadingException;
026import cascading.tuple.io.IndexTuple;
027import org.apache.hadoop.conf.Configurable;
028
029public class IndexTupleCoGroupingComparator extends DeserializerComparator<IndexTuple> implements Configurable
030  {
031  public int compare( byte[] b1, int s1, int l1, byte[] b2, int s2, int l2 )
032    {
033    try
034      {
035      lhsBuffer.reset( b1, s1, l1 );
036      rhsBuffer.reset( b2, s2, l2 );
037
038      int lhsIndex = lhsStream.readVInt();
039      int rhsIndex = rhsStream.readVInt();
040
041      int c = compareTuples( keyTypes, groupComparators );
042
043      if( c != 0 )
044        return c;
045
046      return rhsIndex - lhsIndex;
047      }
048    catch( IOException exception )
049      {
050      throw new CascadingException( exception );
051      }
052    finally
053      {
054      lhsBuffer.clear();
055      rhsBuffer.clear();
056      }
057    }
058
059  public int compare( IndexTuple lhs, IndexTuple rhs )
060    {
061    int c = compareTuples( groupComparators, lhs.getTuple(), rhs.getTuple() );
062
063    if( c != 0 )
064      return c;
065
066    // intentionally sort in reverse
067    return rhs.getIndex() - lhs.getIndex();
068    }
069  }