Java tutorial
/* * Cloud9: A Hadoop toolkit for working with big data * * Licensed under the Apache License, Version 2.0 (the "License"); you * may not use this file except in compliance with the License. You may * obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or * implied. See the License for the specific language governing * permissions and limitations under the License. */ package edu.umd.windmemory; import java.io.IOException; import java.util.Arrays; import java.util.Iterator; import java.util.Set; import java.util.HashSet; import java.util.HashMap; import java.util.ArrayList; import java.io.BufferedReader; import java.io.FileReader; import java.util.StringTokenizer; import java.io.File; import java.net.URI; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.commons.io.FileUtils; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.DoubleWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Partitioner; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.apache.log4j.Logger; import tl.lin.data.pair.PairOfStrings; /** * * <blockquote>Yuan Gao. <b>Scalable Language Processing Algorithms for the Masses: A Case Study in * Computing Word Co-occurrence Matrices with MapReduce.</b> <i>Proceedings of the 2008 Conference * on Empirical Methods in Natural Language Processing (EMNLP 2008)</i>, pages 419-428.</blockquote> * * @author Yuan Gao */ public class PMIPairsR extends Configured implements Tool { private static final Logger LOG = Logger.getLogger(PMIPairsR.class); private static class MyFirstMapper extends Mapper<LongWritable, Text, Text, IntWritable> { private static final Text WORD = new Text(); private static final IntWritable NUM = new IntWritable(1); // private static HashMap<String, Integer> hash = new HashMap<String, Integer>(); // @Override // protected void setup(Context context) { // } @Override public void map(LongWritable key, Text line, Context context) throws IOException, InterruptedException { String text = ((Text) line).toString(); // String[] terms = text.split("\\s+"); StringTokenizer iter = new StringTokenizer(text); HashSet<String> set = new HashSet<String>(); // for (int i = 0; i < terms.length; i++) { // set.add(terms[i]); // } while (iter.hasMoreTokens()) { set.add(iter.nextToken()); } Iterator it = set.iterator(); while (it.hasNext()) { text = (String) it.next(); if (text.length() < 1) continue; // if (hash.containsKey(text)) // hash.put(text, 1); // else // hash.put(text, hash.get(text) + 1); WORD.set(text); context.write(WORD, NUM); } } // @Override // protected void cleanup(Context context) // throws IOException, InterruptedException { // for (Iterator it = hash.keySet().iterator(); it.hasNext(); ) { // String key = (String) it.next(); // WORD.set(key); // NUM.set(hash.get(key)); // context.write(WORD, NUM); // } // } } private static class MyFirstReducer extends Reducer<Text, IntWritable, Text, IntWritable> { private final static IntWritable SUM = new IntWritable(); @Override public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { Iterator<IntWritable> iter = values.iterator(); int sum = 0; while (iter.hasNext()) { sum += iter.next().get(); } SUM.set(sum); context.write(key, SUM); } } private static class MySecondMapper extends Mapper<LongWritable, Text, PairOfStrings, IntWritable> { private static final PairOfStrings PAIR = new PairOfStrings(); private static final IntWritable NUM = new IntWritable(1); // private HashMap<String, Integer> hash = new HashMap<String, Integer>(); // @Override // public void setup(Context context) { // } @Override public void map(LongWritable key, Text line, Context context) throws IOException, InterruptedException { String text = line.toString(); String[] rawterms = text.split("\\s+"); Arrays.sort(rawterms); String prei = " ", prej; for (int i = 0; i < rawterms.length; i++) { if (prei.equals(rawterms[i]) || rawterms[i].length() == 0) continue; prej = " "; for (int j = i + 1; j < rawterms.length; j++) { if (rawterms[i].equals(rawterms[j])) { i = j; continue; } else if (rawterms[j].length() == 0 || prej.equals(rawterms[j])) continue; PAIR.set(rawterms[i], rawterms[j]); context.write(PAIR, NUM); prej = rawterms[j]; } prei = rawterms[i]; } } // @Override // protected void cleanup(Context context) // throws IOException, InterruptedException { // String pair; // String[] terms; // for (Iterator it = hash.keySet().iterator(); it.hasNext(); ) { // pair = (String)it.next(); // terms = pair.split(","); // PAIR.set(terms[0], terms[1]); // NUM.set(hash.get(pair)); // context.write(PAIR, NUM); // } // } } private static class MySecondReducer extends Reducer<PairOfStrings, IntWritable, PairOfStrings, DoubleWritable> { private final static PairOfStrings PAIR = new PairOfStrings(); private final static DoubleWritable RES = new DoubleWritable(); private HashMap<String, Integer> map = new HashMap<String, Integer>(); @Override protected void setup(Context context) throws IOException, InterruptedException { if (context.getCacheFiles() != null) { URI inputURI = context.getCacheFiles()[0]; if (inputURI != null) { String dataStream = FileUtils.readFileToString(new File("./part-r-00000")); String[] terms = dataStream.split("\\s+"); for (int i = 0; i < terms.length; i += 2) { map.put(terms[i], Integer.parseInt(terms[i + 1])); } } } // Configuration conf = context.getConfiguration(); // Integer num = Integer.parseInt(conf.get("num")); // String path = conf.get("path"); // BufferedReader br = null; // for (int i = 0; i < num; i++) { // try { // br = new BufferedReader(new FileReader(path + "/part-r-0000" + i)); // String line = br.readLine(); // Integer val; // while (line != null) { // String[] pair = line.split("\t"); // val = Integer.parseInt(pair[1]); // map.put(pair[0], val); // line = br.readLine(); // } // } catch (IOException e) { // e.printStackTrace(); // } finally { // try { // br.close(); // } catch (IOException e) { // e.printStackTrace(); // } // } // } } @Override public void reduce(PairOfStrings key, Iterable<IntWritable> val, Context context) throws IOException, InterruptedException { Iterator<IntWritable> iter = val.iterator(); int sum = 0; while (iter.hasNext()) { sum += iter.next().get(); } if (sum >= 10) { Double result = (double) sum / (double) map.get(key.getLeftElement()) / (double) map.get(key.getRightElement()); result = Math.log(result) / Math.log(10); RES.set(result); context.write(key, RES); } } } private static class MySecondCombiner extends Reducer<PairOfStrings, IntWritable, PairOfStrings, IntWritable> { private final static PairOfStrings PAIR = new PairOfStrings(); private final static IntWritable NUM = new IntWritable(); @Override public void reduce(PairOfStrings key, Iterable<IntWritable> val, Context context) throws IOException, InterruptedException { Iterator<IntWritable> iter = val.iterator(); int sum = 0; while (iter.hasNext()) { sum += iter.next().get(); } NUM.set(sum); context.write(key, NUM); } } protected static class MyFirstPartitioner extends Partitioner<Text, IntWritable> { @Override public int getPartition(Text key, IntWritable value, int numReduceTasks) { return (key.hashCode() & Integer.MAX_VALUE) % numReduceTasks; } } protected static class MyPartitioner extends Partitioner<PairOfStrings, IntWritable> { @Override public int getPartition(PairOfStrings key, IntWritable value, int numReduceTasks) { return (key.getLeftElement().hashCode() & Integer.MAX_VALUE) % numReduceTasks; } } /** * Creates an instance of this tool. */ public PMIPairsR() { } private static final String INPUT = "input"; private static final String OUTPUT = "output"; private static final String WINDOW = "window"; private static final String NUM_REDUCERS = "numReducers"; /** * Runs this tool. */ @SuppressWarnings({ "static-access" }) public int run(String[] args) throws Exception { Options options = new Options(); options.addOption(OptionBuilder.withArgName("path").hasArg().withDescription("input path").create(INPUT)); options.addOption(OptionBuilder.withArgName("path").hasArg().withDescription("output path").create(OUTPUT)); options.addOption(OptionBuilder.withArgName("num").hasArg().withDescription("window size").create(WINDOW)); options.addOption(OptionBuilder.withArgName("num").hasArg().withDescription("number of reducers") .create(NUM_REDUCERS)); CommandLine cmdline; CommandLineParser parser = new GnuParser(); try { cmdline = parser.parse(options, args); } catch (ParseException exp) { System.err.println("Error parsing command line: " + exp.getMessage()); return -1; } if (!cmdline.hasOption(INPUT) || !cmdline.hasOption(OUTPUT)) { System.out.println("args: " + Arrays.toString(args)); HelpFormatter formatter = new HelpFormatter(); formatter.setWidth(120); formatter.printHelp(this.getClass().getName(), options); ToolRunner.printGenericCommandUsage(System.out); return -1; } String inputPath = cmdline.getOptionValue(INPUT); String outputPath = cmdline.getOptionValue(OUTPUT); int reduceTasks = cmdline.hasOption(NUM_REDUCERS) ? Integer.parseInt(cmdline.getOptionValue(NUM_REDUCERS)) : 1; LOG.info("Tool: " + PMIPairsR.class.getSimpleName()); LOG.info(" - input path: " + inputPath); LOG.info(" - output path: " + outputPath); LOG.info(" - number of reducers: " + reduceTasks); Job job = Job.getInstance(getConf()); job.setJobName(PMIPairsR.class.getSimpleName()); job.setJarByClass(PMIPairsR.class); // Delete the output directory if it exists already. Path interDir = new Path("temp"); FileSystem.get(getConf()).delete(interDir, true); // job.setNumMapTasks(reduceTasks); job.setNumReduceTasks(1); FileInputFormat.setInputPaths(job, new Path(inputPath)); FileOutputFormat.setOutputPath(job, interDir); job.setMapOutputKeyClass(Text.class); job.setMapOutputValueClass(IntWritable.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); job.setMapperClass(MyFirstMapper.class); // job.setCombinerClass(MyFirstReducer.class); job.setReducerClass(MyFirstReducer.class); job.setPartitionerClass(MyFirstPartitioner.class); Job job2 = Job.getInstance(getConf()); job2.setJobName(PMIPairsR.class.getSimpleName()); job2.setJarByClass(PMIPairsR.class); // Delete the output directory if it exists already. Path outputDir = new Path(outputPath); FileSystem.get(getConf()).delete(outputDir, true); // job2.getConfiguration().set("path", "temp"); // job2.getConfiguration().setInt("num", reduceTasks); job2.setNumReduceTasks(reduceTasks); FileInputFormat.setInputPaths(job2, new Path(inputPath)); FileOutputFormat.setOutputPath(job2, new Path(outputPath)); job2.setMapOutputKeyClass(PairOfStrings.class); job2.setMapOutputValueClass(IntWritable.class); job2.setOutputKeyClass(PairOfStrings.class); job2.setOutputValueClass(DoubleWritable.class); job2.setMapperClass(MySecondMapper.class); // job2.setCombinerClass(MySecondCombiner.class); job2.setReducerClass(MySecondReducer.class); job2.setPartitionerClass(MyPartitioner.class); long startTime = System.currentTimeMillis(); job2.addCacheFile(new URI("temp/part-r-00000")); job.waitForCompletion(true); job2.waitForCompletion(true); // FileSystem.get(getConf()).delete(interDir, true); System.out.println("Job Finished in " + (System.currentTimeMillis() - startTime) / 1000.0 + " seconds"); return 0; } /** * Dispatches command-line arguments to the tool via the {@code ToolRunner}. */ public static void main(String[] args) throws Exception { ToolRunner.run(new PMIPairsR(), args); } }