/*
* Cloud9: A MapReduce Library for Hadoop
*
* 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.bfs;
import java.io.IOException;
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.Configured;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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.SequenceFileInputFormat;
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;
import org.apache.log4j.Logger;
/**
* Tool for extracting nodes that are reachable from the source node.
*
* @author Jimmy Lin
*/
public class FindReachableNodes extends Configured implements Tool {
private static final Logger LOG = Logger.getLogger(FindReachableNodes.class);
private static class MyMapper extends Mapper<IntWritable, BfsNode, IntWritable, BfsNode> {
@Override
public void map(IntWritable nid, BfsNode node, Context context)
throws IOException, InterruptedException {
if (node.getDistance() < Integer.MAX_VALUE) {
context.write(nid, node);
}
}
}
public FindReachableNodes() {}
private static final String INPUT_OPTION = "input";
private static final String OUTPUT_OPTION = "output";
@SuppressWarnings("static-access")
@Override
public int run(String[] args) throws Exception {
Options options = new Options();
options.addOption(OptionBuilder.withArgName("path")
.hasArg().withDescription("XML dump file").create(INPUT_OPTION));
options.addOption(OptionBuilder.withArgName("path")
.hasArg().withDescription("output path").create(OUTPUT_OPTION));
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_OPTION) || !cmdline.hasOption(OUTPUT_OPTION)) {
HelpFormatter formatter = new HelpFormatter();
formatter.printHelp(this.getClass().getName(), options);
ToolRunner.printGenericCommandUsage(System.out);
return -1;
}
String inputPath = cmdline.getOptionValue(INPUT_OPTION);
String outputPath = cmdline.getOptionValue(OUTPUT_OPTION);
LOG.info("Tool name: " + this.getClass().getName());
LOG.info(" - inputDir: " + inputPath);
LOG.info(" - outputDir: " + outputPath);
Job job = Job.getInstance(getConf());
job.setJobName(String.format("FindReachableNodes:[%s: %s, %s: %s]", INPUT_OPTION,
inputPath, OUTPUT_OPTION, outputPath));
job.setJarByClass(FindReachableNodes.class);
job.setNumReduceTasks(0);
job.getConfiguration().setInt("mapred.min.split.size", 1024 * 1024 * 1024);
FileInputFormat.addInputPath(job, new Path(inputPath));
FileOutputFormat.setOutputPath(job, new Path(outputPath));
job.setInputFormatClass(SequenceFileInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
job.setMapOutputKeyClass(IntWritable.class);
job.setMapOutputValueClass(BfsNode.class);
job.setOutputKeyClass(IntWritable.class);
job.setOutputValueClass(BfsNode.class);
job.setMapperClass(MyMapper.class);
// Delete the output directory if it exists already.
FileSystem.get(job.getConfiguration()).delete(new Path(outputPath), true);
job.waitForCompletion(true);
return 0;
}
/**
* Dispatches command-line arguments to the tool via the <code>ToolRunner</code>.
*/
public static void main(String[] args) throws Exception {
int res = ToolRunner.run(new FindReachableNodes(), args);
System.exit(res);
}
}