org.sf.xrime.algorithms.partitions.connected.bi.SpanningConvergenceTest.java Source code

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Here is the source code for org.sf.xrime.algorithms.partitions.connected.bi.SpanningConvergenceTest.java

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/*
 * Copyright (C) IBM Corp. 2009.
 * 
 * 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 org.sf.xrime.algorithms.partitions.connected.bi;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.sf.xrime.ProcessorExecutionException;
import org.sf.xrime.algorithms.GraphAlgorithm;
import org.sf.xrime.algorithms.utils.GraphAlgorithmMapReduceBase;
import org.sf.xrime.model.vertex.LabeledAdjSetVertex;

/**
 * This algorithm is used to check for convergence of the spanning tree 
 * construction prcess.
 * @author xue
 *
 */
public class SpanningConvergenceTest extends GraphAlgorithm {
    /**
     * Used as k2.
     */
    private static final Text VERTEXES_OUT_OF_TREE = new Text("out_of_tree");
    /**
     * Used as v2.
     */
    private static final IntWritable ONE = new IntWritable(1);

    /**
     * Default constructor.
     */
    public SpanningConvergenceTest() {
        super();
    }

    /**
     * Check for convergence by counting the number of vertexes which haven't got
     * their PATH_TO_ROOT set.
     * @author xue
     */
    public static class MapClass extends GraphAlgorithmMapReduceBase
            implements Mapper<Text, LabeledAdjSetVertex, Text, IntWritable> {
        @Override
        public void map(Text key, LabeledAdjSetVertex value, OutputCollector<Text, IntWritable> output,
                Reporter reporter) throws IOException {
            if (value.getLabel(ConstantLabels.PATH_TO_ROOT) == null) {
                // Count those vertexes who haven't got their PATH_TO_ROOT set.
                output.collect(VERTEXES_OUT_OF_TREE, ONE);
            }
        }
    }

    @Override
    public void execute() throws ProcessorExecutionException {
        JobConf conf = new JobConf(context, SpanningConvergenceTest.class);
        conf.setJobName("SpanningConvergenceTest");

        // the keys are vertex identifiers (strings)
        conf.setOutputKeyClass(Text.class);
        // the values are integers (Writable)
        conf.setOutputValueClass(IntWritable.class);
        conf.setMapperClass(MapClass.class);
        // makes the file format suitable for machine processing.
        conf.setInputFormat(SequenceFileInputFormat.class);
        try {
            FileInputFormat.setInputPaths(conf, getSource().getPath());
            FileOutputFormat.setOutputPath(conf, getDestination().getPath());
        } catch (IllegalAccessException e1) {
            throw new ProcessorExecutionException(e1);
        }
        conf.setNumMapTasks(getMapperNum());
        conf.setNumReduceTasks(0);

        try {
            this.runningJob = JobClient.runJob(conf);
        } catch (IOException e) {
            throw new ProcessorExecutionException(e);
        }
    }
}