001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.hadoop.sequencefile.combine;
031
032import java.io.IOException;
033
034import org.apache.hadoop.mapreduce.InputSplit;
035import org.apache.hadoop.mapreduce.RecordReader;
036import org.apache.hadoop.mapreduce.TaskAttemptContext;
037import org.apache.hadoop.mapreduce.lib.input.CombineFileSplit;
038import org.apache.hadoop.mapreduce.lib.input.FileSplit;
039import org.apache.hadoop.mapreduce.lib.input.SequenceFileRecordReader;
040import org.apache.hadoop.util.ReflectionUtils;
041
042/**
043 * Proxy RecordReader that CombineFileRecordReader can instantiate, which itself
044 * translates a CombineFileSplit into a FileSplit.
045 * 
046 * @param <K> Key type 
047 * @param <V> Value type
048 */
049public class CombineSequenceFileRecordReader<K, V> extends RecordReader<K, V> {
050        private CombineFileSplit split;
051        private TaskAttemptContext context;
052        private int index;
053        private RecordReader<K, V> rr;
054
055        @SuppressWarnings("unchecked")
056        public CombineSequenceFileRecordReader(CombineFileSplit split, TaskAttemptContext context, Integer index) throws IOException, InterruptedException {
057                this.index = index;
058                this.split = (CombineFileSplit) split;
059                this.context = context;
060
061                this.rr = ReflectionUtils.newInstance(SequenceFileRecordReader.class, context.getConfiguration());
062        }
063
064        @SuppressWarnings("unchecked")
065        @Override
066        public void initialize(InputSplit curSplit, TaskAttemptContext curContext) throws IOException, InterruptedException {
067                this.split = (CombineFileSplit) curSplit;
068                this.context = curContext;
069
070                if (null == rr) {
071                        rr = ReflectionUtils.newInstance(SequenceFileRecordReader.class, context.getConfiguration());
072                }
073
074                FileSplit fileSplit = new FileSplit(this.split.getPath(index),
075                                this.split.getOffset(index), this.split.getLength(index),
076                                this.split.getLocations());
077                
078                this.rr.initialize(fileSplit, this.context);
079        }
080
081        @Override
082        public float getProgress() throws IOException, InterruptedException {
083                return rr.getProgress();
084        }
085
086        @Override
087        public void close() throws IOException {
088                if (null != rr) {
089                        rr.close();
090                        rr = null;
091                }
092        }
093
094        @Override
095        public K getCurrentKey()
096        throws IOException, InterruptedException {
097                return rr.getCurrentKey();
098        }
099
100        @Override
101        public V getCurrentValue()
102        throws IOException, InterruptedException {
103                return rr.getCurrentValue();
104        }
105
106        @Override
107        public boolean nextKeyValue() throws IOException, InterruptedException {
108                return rr.nextKeyValue();
109        }
110}