org.sf.xrime.algorithms.layout.circular.SequentialNumAssign.java Source code

Introduction

Here is the source code for org.sf.xrime.algorithms.layout.circular.SequentialNumAssign.java

Source

/*
 * 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.layout.circular;

import java.io.IOException;
import java.util.Iterator;

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.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.apache.hadoop.mapred.SequenceFileOutputFormat;
import org.sf.xrime.ProcessorExecutionException;
import org.sf.xrime.algorithms.GraphAlgorithm;
import org.sf.xrime.algorithms.layout.ConstantLabels;
import org.sf.xrime.algorithms.utils.GraphAlgorithmMapReduceBase;
import org.sf.xrime.model.vertex.AdjSetVertex;
import org.sf.xrime.model.vertex.LabeledAdjSetVertex;

/**
 * This algorithm is used to assign a sequantial number to each vertex.
 * @author xue
 */
public class SequentialNumAssign extends GraphAlgorithm {
    /**
     * Used to assign sequentail numbers.
     */
    private static final String THE_KEY = "the_key";

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

    /**
     * Mapper.
     * @author xue
     */
    public static class MapClass extends GraphAlgorithmMapReduceBase
            implements Mapper<Text, AdjSetVertex, Text, LabeledAdjSetVertex> {
        @Override
        public void map(Text key, AdjSetVertex value, OutputCollector<Text, LabeledAdjSetVertex> output,
                Reporter reporter) throws IOException {
            output.collect(new Text(THE_KEY), new LabeledAdjSetVertex(value));
        }
    }

    /**
     * Reducer. Single key is used to accummulate all vertexes in order to give
     * sequential numbers to them.
     * @author xue
     *
     */
    public static class ReduceClass extends GraphAlgorithmMapReduceBase
            implements Reducer<Text, LabeledAdjSetVertex, Text, LabeledAdjSetVertex> {

        @Override
        public void reduce(Text key, Iterator<LabeledAdjSetVertex> values,
                OutputCollector<Text, LabeledAdjSetVertex> output, Reporter reporter) throws IOException {
            int sequential_num = 0;
            while (values.hasNext()) {
                LabeledAdjSetVertex curr_vertex = values.next();
                curr_vertex.setLabel(ConstantLabels.SEQUENTIAL_NUM, new IntWritable(sequential_num));
                output.collect(new Text(curr_vertex.getId()), curr_vertex);
                sequential_num++;
            }
        }
    }

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

        conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(LabeledAdjSetVertex.class);
        conf.setMapperClass(MapClass.class);
        // No combiner or reducer is needed.
        conf.setReducerClass(ReduceClass.class);
        // makes the file format suitable for machine processing.
        conf.setInputFormat(SequenceFileInputFormat.class);
        conf.setOutputFormat(SequenceFileOutputFormat.class);
        try {
            FileInputFormat.setInputPaths(conf, getSource().getPath());
            FileOutputFormat.setOutputPath(conf, getDestination().getPath());
        } catch (IllegalAccessException e1) {
            throw new ProcessorExecutionException(e1);
        }
        // The numbers here do not matter.
        conf.setNumMapTasks(getMapperNum());
        conf.setNumReduceTasks(getReducerNum());

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