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.transform.vertex; import java.io.IOException; import java.util.ArrayList; import java.util.List; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; 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.MapReduceBase; 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.apache.hadoop.util.GenericOptionsParser; import org.apache.hadoop.util.ToolRunner; import org.sf.xrime.ProcessorExecutionException; import org.sf.xrime.Transformer; import org.sf.xrime.model.edge.AdjVertexEdge; import org.sf.xrime.model.edge.AdjVertexEdgeWithLabel; import org.sf.xrime.model.vertex.AdjSetVertex; import org.sf.xrime.model.vertex.AdjSetVertexWithTwoHopLabel; import org.sf.xrime.preprocessing.smth.Raw2OutAdjVertexTransformer; /** * Transform AdjSetVertexWithTwoHopLabel into AdjSetVertex. * * @author juwei */ public class AdjSetWithLabel2AdjSetVertexTransformer extends Transformer { /** * Default constructor. */ public AdjSetWithLabel2AdjSetVertexTransformer() { super(); } /** * Another constructor. * * @param src * @param dest */ public AdjSetWithLabel2AdjSetVertexTransformer(Path src, Path dest) { super(src, dest); } /** * Transform AdjSetVertexWithTwoHopLabel into AdjSetVertex * * @author xue */ public static class MapClass extends MapReduceBase implements Mapper<Text, AdjSetVertexWithTwoHopLabel, Text, AdjSetVertex> { @Override public void map(Text key, AdjSetVertexWithTwoHopLabel value, OutputCollector<Text, AdjSetVertex> output, Reporter reporter) throws IOException { AdjSetVertex outputValue = new AdjSetVertex(); outputValue.setId(value.getId()); for (AdjVertexEdgeWithLabel neighbor : value.getNeighbors()) { outputValue.addOpposite(new AdjVertexEdge(neighbor.getOpposite())); } output.collect(key, outputValue); } } /* *//** * Continue to transform the outgoing adjacent vertexes list to * undirected ones, and set appropriate label each vertex. * * @author xue * @author juwei */ /* * public static class ReduceClass extends MapReduceBase implements Reducer<Text, * AdjSetVertex, Text, AdjSetVertex> { * * @Override public void reduce(Text key, Iterator<AdjSetVertex> values, * OutputCollector<Text, AdjSetVertex> output, Reporter reporter) throws * IOException { // TODO } } */ @Override public void execute() throws ProcessorExecutionException { JobConf jobConf = new JobConf(conf, AdjSetWithLabel2AdjSetVertexTransformer.class); jobConf.setJobName("AdjSetWithLabel2AdjSetVertexTransformer"); // the keys are vertex identifiers (strings) jobConf.setOutputKeyClass(Text.class); // the values are adjacent vertexes with labels (Writable) jobConf.setOutputValueClass(AdjSetVertex.class); jobConf.setMapperClass(MapClass.class); // no combiner is needed. // no reduce is needed. // jobConf.setReducerClass(ReduceClass.class); // makes the file format suitable for machine processing. jobConf.setInputFormat(SequenceFileInputFormat.class); jobConf.setOutputFormat(SequenceFileOutputFormat.class); // Enable compression. jobConf.setCompressMapOutput(true); jobConf.setMapOutputCompressorClass(GzipCodec.class); FileInputFormat.setInputPaths(jobConf, srcPath); FileOutputFormat.setOutputPath(jobConf, destPath); jobConf.setNumMapTasks(mapperNum); jobConf.setNumReduceTasks(reducerNum); try { this.runningJob = JobClient.runJob(jobConf); } catch (IOException e) { throw new ProcessorExecutionException(e); } } /** * @param args */ public static void main(String[] args) { try { int res = ToolRunner.run(new AdjSetWithLabel2AdjSetVertexTransformer(), args); System.exit(res); } catch (Exception e) { e.printStackTrace(); } } }