    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  }