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.mode.pointwisemi;
031
032import java.io.BufferedReader;
033import java.io.File;
034import java.io.IOException;
035import java.io.InputStreamReader;
036
037import org.apache.hadoop.fs.FSDataInputStream;
038import org.apache.hadoop.fs.FileSystem;
039import org.apache.hadoop.fs.Path;
040import org.kohsuke.args4j.Option;
041import org.openimaj.hadoop.mapreduce.MultiStagedJob;
042import org.openimaj.hadoop.tools.HadoopToolsUtil;
043import org.openimaj.hadoop.tools.twitter.HadoopTwitterTokenToolOptions;
044import org.openimaj.hadoop.tools.twitter.token.mode.TwitterTokenMode;
045import org.openimaj.hadoop.tools.twitter.token.mode.pointwisemi.count.PairMutualInformation;
046import org.openimaj.hadoop.tools.twitter.token.mode.pointwisemi.sort.PMIPairSort;
047
048/**
049 * Perform DFIDF and output such that each timeslot is a instance and each word a feature
050 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
051 *
052 */
053public class PairwiseMutualInformationMode implements TwitterTokenMode {
054        
055        private MultiStagedJob stages;
056        private String[] fstage;
057        @Option(name="--time-delta", aliases="-t", required=false, usage="The length of a time window in minutes (defaults to -1, i.e. not used, one time period)", metaVar="STRING")
058        private long timeDelta = -1;
059        @Option(name="--min-p-value", aliases="-minp", required=false, usage="The minimum PMI value")
060        double minp = 0;
061        @Option(name="--min-pair-count", aliases="-minpc", required=false, usage="The minimum number of times a pair must occur")
062        int minPairCount = 0;
063
064        @Override
065        public void perform(final HadoopTwitterTokenToolOptions opts) throws Exception {
066                Path outpath = HadoopToolsUtil.getOutputPath(opts);
067                this.stages = new MultiStagedJob(HadoopToolsUtil.getInputPaths(opts),outpath,opts.getArgs());
068                stages.queueStage(new PairMutualInformation(opts.getNonHadoopArgs(),timeDelta));
069                stages.queueStage(new PMIPairSort(minp, minPairCount, outpath));
070                stages.runAll();
071        }
072
073        @Override
074        public String[] finalOutput(HadoopTwitterTokenToolOptions opts) throws Exception {
075                return this.fstage;
076        }
077
078        public static BufferedReader sortedPMIReader(File outputLocation) throws IOException {
079                Path path = HadoopToolsUtil.getInputPaths(outputLocation.getAbsolutePath() + Path.SEPARATOR + PMIPairSort.PMI_NAME)[0];
080                FileSystem fs = HadoopToolsUtil.getFileSystem(path);
081                FSDataInputStream is = fs.open(path);
082                return new BufferedReader(new InputStreamReader(is,"UTF-8"));
083        }
084        
085}