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 cascading.tuple.Tuple;
024    import org.apache.hadoop.mapred.Partitioner;
025    
026    /**
027     * GroupingPartitioner is a Partitioner based on the hashCode of the tuple. It honors custom Hasher implementations if
028     * present.
029     */
030    public class GroupingPartitioner  extends HasherPartitioner implements Partitioner<Tuple, Tuple>
031      {
032      @Override
033      public int getPartition( Tuple key, Tuple value, int numReduceTasks )
034        {
035        return ( hashCode( key ) & Integer.MAX_VALUE ) % numReduceTasks;
036        }
037      }