001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.mapred.join;
020    
021    import java.io.IOException;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    import org.apache.hadoop.io.WritableComparable;
026    import org.apache.hadoop.io.WritableComparator;
027    import org.apache.hadoop.mapred.JobConf;
028    
029    /**
030     * Full outer join.
031     */
032    @InterfaceAudience.Public
033    @InterfaceStability.Stable
034    public class OuterJoinRecordReader<K extends WritableComparable>
035        extends JoinRecordReader<K> {
036    
037      OuterJoinRecordReader(int id, JobConf conf, int capacity,
038          Class<? extends WritableComparator> cmpcl) throws IOException {
039        super(id, conf, capacity, cmpcl);
040      }
041    
042      /**
043       * Emit everything from the collector.
044       */
045      protected boolean combine(Object[] srcs, TupleWritable dst) {
046        assert srcs.length == dst.size();
047        return true;
048      }
049    }