001    /*
002     * Copyright (c) 2007-2014 Concurrent, 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    
021    package cascading.tuple.hadoop.util;
022    
023    import java.io.IOException;
024    
025    import cascading.CascadingException;
026    import cascading.tuple.io.TuplePair;
027    
028    /** Class GroupingComparator is an implementation of {@link org.apache.hadoop.io.RawComparator}. */
029    public 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( 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      }