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.TuplePair;
027
028/** Class GroupingComparator is an implementation of {@link org.apache.hadoop.io.RawComparator}. */
029public class GroupingComparator extends DeserializerComparator<TuplePair>
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      // only compare the first tuple in the pair
039      return compareTuples( keyTypes, groupComparators );
040      }
041    catch( IOException exception )
042      {
043      throw new CascadingException( exception );
044      }
045    finally
046      {
047      lhsBuffer.clear();
048      rhsBuffer.clear();
049      }
050    }
051
052  public int compare( TuplePair lhs, TuplePair rhs )
053    {
054    return compareTuples( groupComparators, lhs.getLhs(), rhs.getLhs() );
055    }
056  }