Java tutorial
/* * Cloud9: A Hadoop toolkit for working with big data * * 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 edu.umd.cloud9.example.pagerank; import java.io.IOException; import java.util.Arrays; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; 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.SequenceFileOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.apache.log4j.Logger; import edu.umd.cloud9.io.array.ArrayListOfIntsWritable; import edu.umd.cloud9.io.map.HMapIFW; import pagerank.PageRankNodeMultiSrc; //import pagerank.PageRankNodeMultiSrc; /** * <p> * Driver program that takes a plain-text encoding of a directed graph and builds corresponding * Hadoop structures for representing the graph. * </p> * */ public class BuildPersonalizedPageRankRecords extends Configured implements Tool { private static final Logger LOG = Logger.getLogger(BuildPersonalizedPageRankRecords.class); private static final String NODE_CNT_FIELD = "node.cnt"; private static final String NODE_SRC = "source_pagerank"; private static class MyMapper extends Mapper<LongWritable, Text, IntWritable, PageRankNodeMultiSrc> { private static final IntWritable nid = new IntWritable(); private static final PageRankNodeMultiSrc node = new PageRankNodeMultiSrc(); private static String SrcNode; private static int[] src; @Override public void setup(Mapper<LongWritable, Text, IntWritable, PageRankNodeMultiSrc>.Context context) { int n = context.getConfiguration().getInt(NODE_CNT_FIELD, 0); SrcNode = context.getConfiguration().get(NODE_SRC); if (n == 0) { throw new RuntimeException(NODE_CNT_FIELD + " cannot be 0!"); } String[] sources = SrcNode.split(","); //System.out.print(sources[0]+sources[1]+"\n\n\n\n"); src = new int[sources.length]; for (int i = 0; i < sources.length; i++) { src[i] = Integer.parseInt(sources[i]); } node.setType(PageRankNodeMultiSrc.Type.Complete); node.setPageRank(0); //unused node.setSrcNode(src); } @Override public void map(LongWritable key, Text t, Context context) throws IOException, InterruptedException { String[] arr = t.toString().trim().split("\\s+"); nid.set(Integer.parseInt(arr[0])); if (arr.length == 1) { node.setNodeId(Integer.parseInt(arr[0])); node.setAdjacencyList(new ArrayListOfIntsWritable()); } else { node.setNodeId(Integer.parseInt(arr[0])); int[] neighbors = new int[arr.length - 1]; for (int i = 1; i < arr.length; i++) { neighbors[i - 1] = Integer.parseInt(arr[i]); } node.setAdjacencyList(new ArrayListOfIntsWritable(neighbors)); } context.getCounter("graph", "numNodes").increment(1); context.getCounter("graph", "numEdges").increment(arr.length - 1); if (arr.length > 1) { context.getCounter("graph", "numActiveNodes").increment(1); } for (int i = 0; i < src.length; i++) { if (nid.get() == src[i]) { node.setSrcNodePG(src[i], 1.0f); context.write(nid, node); node.setSrcNodePG(src[i], 0.0f); return; } else { continue; } } context.write(nid, node); } } public BuildPersonalizedPageRankRecords() { } private static final String INPUT = "input"; private static final String OUTPUT = "output"; private static final String NUM_NODES = "numNodes"; private static final String SOURCES = "sources"; /** * Runs this tool. */ @SuppressWarnings({ "static-access" }) public int run(String[] args) throws Exception { Options options = new Options(); options.addOption(OptionBuilder.withArgName("path").hasArg().withDescription("input path").create(INPUT)); options.addOption(OptionBuilder.withArgName("path").hasArg().withDescription("output path").create(OUTPUT)); options.addOption( OptionBuilder.withArgName("num").hasArg().withDescription("number of nodes").create(NUM_NODES)); //parsing more than 1 integer later; options.addOption( OptionBuilder.withArgName("src").hasArg().withDescription("source of pagerank").create(SOURCES)); CommandLine cmdline; CommandLineParser parser = new GnuParser(); try { cmdline = parser.parse(options, args); } catch (ParseException exp) { System.err.println("Error parsing command line: " + exp.getMessage()); return -1; } if (!cmdline.hasOption(INPUT) || !cmdline.hasOption(OUTPUT) || !cmdline.hasOption(NUM_NODES) || !cmdline.hasOption(SOURCES)) { System.out.println("args: " + Arrays.toString(args)); HelpFormatter formatter = new HelpFormatter(); formatter.setWidth(120); formatter.printHelp(this.getClass().getName(), options); ToolRunner.printGenericCommandUsage(System.out); return -1; } String inputPath = cmdline.getOptionValue(INPUT); String outputPath = cmdline.getOptionValue(OUTPUT); int n = Integer.parseInt(cmdline.getOptionValue(NUM_NODES)); //Change to array later String src = cmdline.getOptionValue(SOURCES); LOG.info("Tool name: " + BuildPersonalizedPageRankRecords.class.getSimpleName()); LOG.info(" - inputDir: " + inputPath); LOG.info(" - outputDir: " + outputPath); LOG.info(" - numNodes: " + n); Configuration conf = getConf(); conf.setInt(NODE_CNT_FIELD, n); //more to be set later; conf.set(NODE_SRC, src); conf.setInt("mapred.min.split.size", 1024 * 1024 * 1024); Job job = Job.getInstance(conf); job.setJobName(BuildPersonalizedPageRankRecords.class.getSimpleName() + ":" + inputPath); job.setJarByClass(BuildPersonalizedPageRankRecords.class); job.setNumReduceTasks(0); FileInputFormat.addInputPath(job, new Path(inputPath)); FileOutputFormat.setOutputPath(job, new Path(outputPath)); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(SequenceFileOutputFormat.class); job.setMapOutputKeyClass(IntWritable.class); job.setMapOutputValueClass(PageRankNodeMultiSrc.class); job.setOutputKeyClass(IntWritable.class); job.setOutputValueClass(PageRankNodeMultiSrc.class); job.setMapperClass(MyMapper.class); // Delete the output directory if it exists already. FileSystem.get(conf).delete(new Path(outputPath), true); job.waitForCompletion(true); return 0; } /** * Dispatches command-line arguments to the tool via the {@code ToolRunner}. */ public static void main(String[] args) throws Exception { ToolRunner.run(new BuildPersonalizedPageRankRecords(), args); } }