edu.umd.cloud9.pagerank.BuildPageRankRecords.java Source code

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Here is the source code for edu.umd.cloud9.pagerank.BuildPageRankRecords.java

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/*
 * Cloud9: A MapReduce Library for Hadoop
 *
 * 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.cloud9.pagerank;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
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.Text;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileOutputFormat;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.lib.IdentityReducer;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.log4j.Logger;

import edu.umd.cloud9.io.ArrayListOfIntsWritable;

/**
 * <p>
 * Driver program that takes a plain-text encoding of a directed graph and
 * builds corresponding Hadoop structures for representing the graph.
 * Command-line parameters are as follows:
 * </p>
 * 
 * <ul>
 * 
 * <li>[inputDir]: input directory</li>
 * <li>[outputDir]: output directory</li>
 * <li>[numNodes]: number of nodes in the graph</li>
 * 
 * </ul>
 * 
 * @author Jimmy Lin
 * @author Michael Schatz
 * 
 */
public class BuildPageRankRecords extends Configured implements Tool {

    private static final Logger sLogger = Logger.getLogger(BuildPageRankRecords.class);

    private static class MyMapper extends MapReduceBase
            implements Mapper<LongWritable, Text, IntWritable, PageRankNode> {

        private static IntWritable nid = new IntWritable();
        private static PageRankNode node = new PageRankNode();

        public void configure(JobConf job) {
            int n = job.getInt("NodeCnt", 0);
            node.setType(PageRankNode.TYPE_COMPLETE);
            node.setPageRank((float) -StrictMath.log(n));
        }

        public void map(LongWritable key, Text t, OutputCollector<IntWritable, PageRankNode> output,
                Reporter reporter) throws IOException {

            String[] arr = t.toString().trim().split("\\s+");

            nid.set(Integer.parseInt(arr[0]));
            if (arr.length == 1) {
                node.setNodeId(Integer.parseInt(arr[0]));
                node.setAdjacencyList(new ArrayListOfIntsWritable());

            } else {
                node.setNodeId(Integer.parseInt(arr[0]));

                int[] neighbors = new int[arr.length - 1];
                for (int i = 1; i < arr.length; i++) {
                    neighbors[i - 1] = Integer.parseInt(arr[i]);
                }

                node.setAdjacencyList(new ArrayListOfIntsWritable(neighbors));
            }

            reporter.incrCounter("graph", "numNodes", 1);
            reporter.incrCounter("graph", "numEdges", arr.length - 1);

            if (arr.length > 1) {
                reporter.incrCounter("graph", "numActiveNodes", 1);
            }

            output.collect(nid, node);
        }
    }

    public BuildPageRankRecords() {
    }

    private static int printUsage() {
        System.out.println("usage: [inputDir] [outputDir] [numNodes]");
        ToolRunner.printGenericCommandUsage(System.out);
        return -1;
    }

    /**
     * Runs this tool.
     */
    public int run(String[] args) throws Exception {
        if (args.length != 3) {
            printUsage();
            return -1;
        }

        String inputPath = args[0];
        String outputPath = args[1];
        int n = Integer.parseInt(args[2]);

        sLogger.info("Tool name: BuildPageRankRecords");
        sLogger.info(" - inputDir: " + inputPath);
        sLogger.info(" - outputDir: " + outputPath);
        sLogger.info(" - numNodes: " + n);

        JobConf conf = new JobConf(BuildPageRankRecords.class);
        conf.setJobName("PackageLinkGraph");

        conf.setNumMapTasks(1);
        conf.setNumReduceTasks(0);

        conf.setInt("NodeCnt", n);
        conf.setInt("mapred.min.split.size", 1024 * 1024 * 1024);

        TextInputFormat.addInputPath(conf, new Path(inputPath));
        SequenceFileOutputFormat.setOutputPath(conf, new Path(outputPath));

        conf.setInputFormat(TextInputFormat.class);
        conf.setOutputFormat(SequenceFileOutputFormat.class);

        conf.setMapOutputKeyClass(IntWritable.class);
        conf.setMapOutputValueClass(PageRankNode.class);

        conf.setOutputKeyClass(IntWritable.class);
        conf.setOutputValueClass(PageRankNode.class);

        conf.setMapperClass(MyMapper.class);
        conf.setReducerClass(IdentityReducer.class);

        // delete the output directory if it exists already
        FileSystem.get(conf).delete(new Path(outputPath), true);

        JobClient.runJob(conf);

        return 0;
    }

    /**
     * Dispatches command-line arguments to the tool via the
     * <code>ToolRunner</code>.
     */
    public static void main(String[] args) throws Exception {
        int res = ToolRunner.run(new Configuration(), new BuildPageRankRecords(), args);
        System.exit(res);
    }
}