Java tutorial
/* * 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.gfr; import java.io.IOException; import java.util.Iterator; import org.apache.hadoop.io.DoubleWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.compress.GzipCodec; 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 summarize displacements caused by repulsive force (this part has * already been summarized in RepulsiveForceDisp) and attractive force (this part need to be * summarized and the added to the repulsive part). * @author xue */ public class DisplacementSummarize extends GraphAlgorithm { /** * Default constructor. */ public DisplacementSummarize() { super(); } /** * Mapper. Just re-emit it. * @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 { output.collect(key, value); } } /** * Calculate new coordinates for each vertex. * @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 { // 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)); // Get the temperature. int temperature = Integer.parseInt(context.getParameter(ConstantLabels.TEMPERATURE)); LabeledAdjSetVertex result = null; PlaneVector v_pos = null; PlaneVector v_disp = new PlaneVector(0, 0); while (values.hasNext()) { LabeledAdjSetVertex curr_vertex = values.next(); if (curr_vertex.getLabel(ConstantLabels.X_COORDINATE) != null) { // This is the main one. // Create a new LabeledAdjVertex. result = new LabeledAdjSetVertex((AdjSetVertex) curr_vertex); // Determine the original coordinates. double x_coordinate = ((DoubleWritable) curr_vertex.getLabel(ConstantLabels.X_COORDINATE)) .get(); double y_coordinate = ((DoubleWritable) curr_vertex.getLabel(ConstantLabels.Y_COORDINATE)) .get(); v_pos = new PlaneVector(x_coordinate, y_coordinate); // Determine the displacement. double x_disp = ((DoubleWritable) curr_vertex.getLabel(ConstantLabels.X_DISP)).get(); double y_disp = ((DoubleWritable) curr_vertex.getLabel(ConstantLabels.Y_DISP)).get(); PlaneVector temp_vec = new PlaneVector(x_disp, y_disp); v_disp = v_disp.plus(temp_vec); } else { // Determine the displacement. double x_disp = ((DoubleWritable) curr_vertex.getLabel(ConstantLabels.X_DISP)).get(); double y_disp = ((DoubleWritable) curr_vertex.getLabel(ConstantLabels.Y_DISP)).get(); PlaneVector temp_vec = new PlaneVector(x_disp, y_disp); v_disp = v_disp.plus(temp_vec); } } if (v_pos == null || result == null) { return; // Something wrong. } // Update the coordinates of this vertex. v_pos = v_pos.plus(v_disp.normalize() .multiply_scalar(v_disp.magnitude() > temperature ? temperature : v_disp.magnitude())); double new_x_coordinate = -1; double new_y_coordinate = -1; if (max_x > v_pos.getX()) { if (v_pos.getX() > 0) { new_x_coordinate = v_pos.getX(); } else { new_x_coordinate = 0; } } else { new_x_coordinate = max_x; } if (max_y > v_pos.getY()) { if (v_pos.getY() > 0) { new_y_coordinate = v_pos.getY(); } else { new_y_coordinate = 0; } } else { new_y_coordinate = max_y; } result.setLabel(ConstantLabels.X_COORDINATE, new DoubleWritable(new_x_coordinate)); result.setLabel(ConstantLabels.Y_COORDINATE, new DoubleWritable(new_y_coordinate)); // Collect it. output.collect(key, result); } } @Override public void execute() throws ProcessorExecutionException { JobConf conf = new JobConf(context, DisplacementSummarize.class); conf.setJobName("DisplacementSummarize"); conf.setOutputKeyClass(Text.class); conf.setOutputValueClass(LabeledAdjSetVertex.class); conf.setMapperClass(MapClass.class); // No combiner is permitted, since the logic of reducer depends on the completeness // of information. conf.setReducerClass(ReduceClass.class); // makes the file format suitable for machine processing. conf.setInputFormat(SequenceFileInputFormat.class); conf.setOutputFormat(SequenceFileOutputFormat.class); // Enable compression. conf.setCompressMapOutput(true); conf.setMapOutputCompressorClass(GzipCodec.class); try { FileInputFormat.setInputPaths(conf, getSource().getPath()); FileOutputFormat.setOutputPath(conf, getDestination().getPath()); } catch (IllegalAccessException e1) { throw new ProcessorExecutionException(e1); } conf.setNumMapTasks(getMapperNum()); conf.setNumReduceTasks(getReducerNum()); try { this.runningJob = JobClient.runJob(conf); } catch (IOException e) { throw new ProcessorExecutionException(e); } } }