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

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Here is the source code for org.sf.xrime.algorithms.layout.circular.CoordinatesCalculation.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.layout.circular;

import java.io.IOException;

import org.apache.hadoop.io.DoubleWritable;
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.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 calculate the coordinates of each vertex according to its
 * sequential number.
 * @author xue
 */
public class CoordinatesCalculation extends GraphAlgorithm {
    /**
     * Default constructor.
     */
    public CoordinatesCalculation() {
        super();
    }

    /**
     * Calculate the coordinate for each vertex according to its sequential number.
     * The number assignment is sequantial, but this calculation could be parallel.
     * @author xue
     */
    public static class MapClass extends GraphAlgorithmMapReduceBase
            implements Mapper<Text, LabeledAdjSetVertex, Text, LabeledAdjSetVertex> {

        @Override
        public void map(Text key, LabeledAdjSetVertex value, OutputCollector<Text, LabeledAdjSetVertex> output,
                Reporter reporter) throws IOException {
            // Get the specified size of the display frame.
            int max_x = Integer.parseInt(context.getParameter(ConstantLabels.MAX_X_COORDINATE));
            int max_y = Integer.parseInt(context.getParameter(ConstantLabels.MAX_Y_COORDINATE));
            int num_of_vertexes = Integer.parseInt(context.getParameter(ConstantLabels.NUM_OF_VERTEXES));

            // We assume the coordinates are counted as the numbers of pixels from the upper-left corner
            // of the display frame.
            int origin_x = max_x / 2;
            int origin_y = max_y / 2;
            // 9/10 is used in order to keep distance from edges of the display frame.
            int radius = (max_x > max_y ? max_y / 2 : max_x / 2) - (max_x > max_y ? max_y / 2 : max_x / 2) / 10;

            // Calcualte coordinates.
            int seq_num = ((IntWritable) value.getLabel(ConstantLabels.SEQUENTIAL_NUM)).get();
            double x_coordinate = origin_x + radius * Math.cos(seq_num * ((2 * Math.PI) / num_of_vertexes));
            double y_coordinate = origin_y - radius * Math.sin(seq_num * ((2 * Math.PI) / num_of_vertexes));

            LabeledAdjSetVertex result = new LabeledAdjSetVertex((AdjSetVertex) value);

            result.setLabel(ConstantLabels.X_COORDINATE, new DoubleWritable(x_coordinate));
            result.setLabel(ConstantLabels.Y_COORDINATE, new DoubleWritable(y_coordinate));
            output.collect(key, result);
        }
    }

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

        conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(LabeledAdjSetVertex.class);
        conf.setMapperClass(MapClass.class);
        // No combiner or reducer is needed.
        // 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);
        }
        // Only one mapper is permitted.
        conf.setNumMapTasks(getMapperNum());
        conf.setNumReduceTasks(0);

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