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.mapreduce.lib.input;
020
021import java.io.IOException;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.mapreduce.InputSplit;
026import org.apache.hadoop.mapreduce.RecordReader;
027import org.apache.hadoop.mapreduce.TaskAttemptContext;
028
029/**
030 * Input format that is a <code>CombineFileInputFormat</code>-equivalent for
031 * <code>SequenceFileInputFormat</code>.
032 *
033 * @see CombineFileInputFormat
034 */
035@InterfaceAudience.Public
036@InterfaceStability.Stable
037public class CombineSequenceFileInputFormat<K,V>
038  extends CombineFileInputFormat<K,V> {
039  @SuppressWarnings({ "rawtypes", "unchecked" })
040  public RecordReader<K,V> createRecordReader(InputSplit split,
041    TaskAttemptContext context) throws IOException {
042    return new CombineFileRecordReader((CombineFileSplit)split, context,
043      SequenceFileRecordReaderWrapper.class);
044  }
045
046  /**
047   * A record reader that may be passed to <code>CombineFileRecordReader</code>
048   * so that it can be used in a <code>CombineFileInputFormat</code>-equivalent
049   * for <code>SequenceFileInputFormat</code>.
050   *
051   * @see CombineFileRecordReader
052   * @see CombineFileInputFormat
053   * @see SequenceFileInputFormat
054   */
055  private static class SequenceFileRecordReaderWrapper<K,V>
056    extends CombineFileRecordReaderWrapper<K,V> {
057    // this constructor signature is required by CombineFileRecordReader
058    public SequenceFileRecordReaderWrapper(CombineFileSplit split,
059      TaskAttemptContext context, Integer idx)
060      throws IOException, InterruptedException {
061      super(new SequenceFileInputFormat<K,V>(), split, context, idx);
062    }
063  }
064}