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.tools.twitter.token.outputmode.jacard;
031
032import java.io.DataInput;
033import java.io.IOException;
034import java.util.ArrayList;
035
036import org.apache.hadoop.io.BytesWritable;
037import org.apache.hadoop.io.LongWritable;
038import org.apache.hadoop.io.Text;
039import org.apache.hadoop.mapreduce.Mapper;
040import org.openimaj.hadoop.tools.twitter.utils.WordDFIDF;
041import org.openimaj.io.IOUtils;
042import org.openimaj.io.wrappers.ReadableListBinary;
043
044/**
045 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
046 *
047 * A mapper which given a word with many {@link WordDFIDF} entries, outputs the word as value and the earliest time as key
048 */
049public class TimeWordMapper extends Mapper<Text, BytesWritable, LongWritable, Text> {
050        
051        /**
052         * 
053         */
054        public TimeWordMapper() {}
055        
056        @Override
057        protected void map(final Text key, BytesWritable value, final org.apache.hadoop.mapreduce.Mapper<Text,BytesWritable,LongWritable,Text>.Context context) throws java.io.IOException ,InterruptedException {
058                try {
059                        IOUtils.deserialize(value.getBytes(), new ReadableListBinary<Object>(new ArrayList<Object>()){
060                                @Override
061                                protected Object readValue(DataInput in) throws IOException {
062                                        WordDFIDF idf = new WordDFIDF();
063                                        idf.readBinary(in);
064                                        
065                                        try {
066                                                context.write(new LongWritable(idf.timeperiod), key);
067                                        } catch (InterruptedException e) {
068                                                throw new IOException(e);
069                                        }
070                                        return new Object();
071                                }
072                        });
073                } catch (IOException e) {
074                        System.err.println("Couldnt read word: " + key);
075                }
076        };
077}