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
019package org.apache.hadoop.mapred.join;
020
021import java.io.IOException;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.io.WritableComparable;
026import org.apache.hadoop.io.WritableComparator;
027import org.apache.hadoop.mapred.JobConf;
028
029/**
030 * Full outer join.
031 */
032@InterfaceAudience.Public
033@InterfaceStability.Stable
034public 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}