Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package com.bark.hadoop.lab3; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Date; import java.util.logging.Level; import java.util.logging.Logger; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.FSDataInputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.LocatedFileStatus; import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.RemoteIterator; import org.apache.hadoop.io.DoubleWritable; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.TextInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; public class PageRank extends Configured implements Tool { public static void main(String[] args) throws Exception { int res = ToolRunner.run(new Configuration(), new PageRank(), args); System.exit(res); } @Override public int run(String args[]) { String tmp = "/tmp/" + new Date().getTime(); // long timeStamp = new Date().getTime(); try { /** * Job 1: Parse XML input and read title,links */ Configuration conf = new Configuration(); conf.set("xmlinput.start", "<page>"); conf.set("xmlinput.end", "</page>"); Job job = Job.getInstance(conf); job.setJarByClass(PageRank.class); // specify a mapper job.setMapperClass(RedLinkMapper.class); // specify a reducer job.setReducerClass(RedLinkReducer.class); // specify output types job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); // specify input and output DIRECTORIES FileInputFormat.addInputPath(job, new Path(args[0])); job.setInputFormatClass(XmlInputFormat.class); FileOutputFormat.setOutputPath(job, new Path((args[1] + tmp + "/job1"))); job.setOutputFormatClass(TextOutputFormat.class); job.waitForCompletion(true); } catch (InterruptedException | ClassNotFoundException | IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error during mapreduce job1."); return 2; } /** * Job 2: Adjacency outGraph */ try { Configuration conf2 = new Configuration(); Job job2 = Job.getInstance(conf2); job2.setJarByClass(PageRank.class); // specify a mapper job2.setMapperClass(AdjMapper.class); // specify a reducer job2.setReducerClass(AdjReducer.class); // specify output types job2.setOutputKeyClass(Text.class); job2.setOutputValueClass(Text.class); // specify input and output DIRECTORIES FileInputFormat.addInputPath(job2, new Path((args[1] + tmp + "/job1"))); job2.setInputFormatClass(TextInputFormat.class); FileOutputFormat.setOutputPath(job2, new Path((args[1] + tmp + "/job2"))); job2.setOutputFormatClass(TextOutputFormat.class); job2.waitForCompletion(true); } catch (InterruptedException | ClassNotFoundException | IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error during mapreduce job2."); return 2; } /** * Job 3: PageCount */ try { Configuration conf3 = new Configuration(); /** * Change output separator to "=" instead of default \t for this job */ conf3.set("mapreduce.output.textoutputformat.separator", "="); Job job3 = Job.getInstance(conf3); job3.setJarByClass(PageRank.class); // specify a mapper job3.setMapperClass(PageCountMapper.class); // specify a reducer job3.setReducerClass(PageCountReducer.class); // specify output types job3.setOutputKeyClass(Text.class); job3.setOutputValueClass(IntWritable.class); // specify input and output DIRECTORIES FileInputFormat.addInputPath(job3, new Path((args[1] + tmp + "/job2"))); job3.setInputFormatClass(TextInputFormat.class); FileOutputFormat.setOutputPath(job3, new Path((args[1] + tmp + "/job3"))); job3.setOutputFormatClass(TextOutputFormat.class); job3.waitForCompletion(true); } catch (InterruptedException | ClassNotFoundException | IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error during mapreduce job3."); return 2; } /** * Job 4: PageRank */ for (int i = 1; i < 9; i++) { try { Configuration conf4 = new Configuration(); /** * Read number of nodes from the output of job 3 : pageCount */ Path path = new Path((args[1] + tmp + "/job3")); FileSystem fs = path.getFileSystem(conf4); RemoteIterator<LocatedFileStatus> ri = fs.listFiles(path, true); int n = 0; Pattern pt = Pattern.compile("(\\d+)"); while (ri.hasNext()) { LocatedFileStatus lfs = ri.next(); if (lfs.isFile() && n == 0) { FSDataInputStream inputStream = fs.open(lfs.getPath()); BufferedReader br = new BufferedReader(new InputStreamReader(inputStream)); String s = null; while ((s = br.readLine()) != null) { Matcher mt = pt.matcher(s); if (mt.find()) { n = new Integer(mt.group(1)); break; } } } } /** * Done reading number of nodes, make it available to MapReduce * job key: N */ conf4.setInt("N", n); Job job4 = Job.getInstance(conf4); job4.setJarByClass(PageRank.class); // specify a mapper job4.setMapperClass(PageRankMapper.class); // specify a reducer job4.setReducerClass(PageRankReducer.class); // specify output types job4.setOutputKeyClass(Text.class); job4.setOutputValueClass(Text.class); // specify input and output DIRECTORIES if (i == 1) { FileInputFormat.addInputPath(job4, new Path((args[1] + tmp + "/job2"))); } else { FileInputFormat.addInputPath(job4, new Path((args[1] + tmp + "/job4/" + (i - 1)))); } job4.setInputFormatClass(TextInputFormat.class); FileOutputFormat.setOutputPath(job4, new Path((args[1] + tmp + "/job4/" + i))); job4.setOutputFormatClass(TextOutputFormat.class); job4.waitForCompletion(true); } catch (InterruptedException | ClassNotFoundException | IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error during mapreduce job4."); return 2; } } /** * Job 5: Sort iteration 1 and iteration 8 */ int returnCode = 0; for (int i = 0; i < 2; i++) { try { Configuration conf5 = new Configuration(); /** * Read number of nodes from the output of job 3 : pageCount */ Path path = new Path((args[1] + tmp + "/job3")); FileSystem fs = path.getFileSystem(conf5); RemoteIterator<LocatedFileStatus> ri = fs.listFiles(path, true); int n = 0; Pattern pt = Pattern.compile("(\\d+)"); while (ri.hasNext()) { LocatedFileStatus lfs = ri.next(); if (lfs.isFile() && n == 0) { FSDataInputStream inputStream = fs.open(lfs.getPath()); BufferedReader br = new BufferedReader(new InputStreamReader(inputStream)); String s = null; while ((s = br.readLine()) != null) { Matcher mt = pt.matcher(s); if (mt.find()) { n = new Integer(mt.group(1)); break; } } } } /** * Done reading number of nodes, make it available to MapReduce * job key: N */ conf5.setInt("N", n); Job job5 = Job.getInstance(conf5); /** * one reducer only */ job5.setNumReduceTasks(1); job5.setSortComparatorClass(MyWritableComparator.class); job5.setJarByClass(PageRank.class); // specify a mapper job5.setMapperClass(SortMapper.class); job5.setMapOutputKeyClass(DoubleWritable.class); job5.setMapOutputValueClass(Text.class); // specify a reducer job5.setReducerClass(SortReducer.class); // specify output types job5.setOutputKeyClass(Text.class); job5.setOutputValueClass(DoubleWritable.class); // specify input and output DIRECTORIES int y = 7 * i + 1; FileInputFormat.addInputPath(job5, new Path((args[1] + tmp + "/job4/" + y))); job5.setInputFormatClass(TextInputFormat.class); FileOutputFormat.setOutputPath(job5, new Path((args[1] + tmp + "/job5/" + y))); job5.setOutputFormatClass(TextOutputFormat.class); returnCode = job5.waitForCompletion(true) ? 0 : 1; } catch (InterruptedException | ClassNotFoundException | IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error during mapreduce job5."); return 2; } } /** * Copy necessary output files to args[1] /** * Copy necessary output files to args[1] */ /** * Rename and copy OutLinkGraph */ try { Configuration conf = new Configuration(); Path outLinkGraph = new Path((args[1] + tmp + "/job2/part-r-00000")); FileSystem outLinkGraphFS = outLinkGraph.getFileSystem(conf); Path output = new Path(args[1] + "/results/PageRank.outlink.out"); FileSystem outputFS = output.getFileSystem(conf); org.apache.hadoop.fs.FileUtil.copy(outLinkGraphFS, outLinkGraph, outputFS, output, false, true, conf); } catch (IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error while copying results."); return 2; } /** * Rename and copy total number of pages */ try { Configuration conf = new Configuration(); Path outLinkGraph = new Path((args[1] + tmp + "/job3/part-r-00000")); FileSystem outLinkGraphFS = outLinkGraph.getFileSystem(conf); Path output = new Path(args[1] + "/results/PageRank.n.out"); FileSystem outputFS = output.getFileSystem(conf); org.apache.hadoop.fs.FileUtil.copy(outLinkGraphFS, outLinkGraph, outputFS, output, false, true, conf); } catch (IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error while copying results."); return 2; } /** * Rename and copy iteration 1 */ try { Configuration conf = new Configuration(); Path outLinkGraph = new Path((args[1] + tmp + "/job5/1/part-r-00000")); FileSystem outLinkGraphFS = outLinkGraph.getFileSystem(conf); Path output = new Path(args[1] + "/results/PageRank.iter1.out"); FileSystem outputFS = output.getFileSystem(conf); org.apache.hadoop.fs.FileUtil.copy(outLinkGraphFS, outLinkGraph, outputFS, output, false, true, conf); } catch (IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error while copying results."); return 2; } /** * Rename and copy iteration 8 */ try { Configuration conf = new Configuration(); Path outLinkGraph = new Path((args[1] + tmp + "/job5/8/part-r-00000")); FileSystem outLinkGraphFS = outLinkGraph.getFileSystem(conf); Path output = new Path(args[1] + "/results/PageRank.iter8.out"); FileSystem outputFS = output.getFileSystem(conf); org.apache.hadoop.fs.FileUtil.copy(outLinkGraphFS, outLinkGraph, outputFS, output, false, true, conf); } catch (IOException ex) { Logger.getLogger(PageRank.class.getName()).log(Level.SEVERE, ex.toString(), ex); System.err.println("Error while copying results."); return 2; } return returnCode; } }