/**
* Copyright 2005 The Apache Software Foundation
*
* 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.apache.nutch.mapReduce.demo;
import org.apache.nutch.mapReduce.JobConf;
import org.apache.nutch.mapReduce.JobClient;
import org.apache.nutch.mapReduce.RunningJob;
import org.apache.nutch.mapReduce.InputFormats;
import org.apache.nutch.mapReduce.OutputFormats;
import org.apache.nutch.mapReduce.lib.RegexMapper;
import org.apache.nutch.mapReduce.lib.InverseMapper;
import org.apache.nutch.mapReduce.lib.LongSumReducer;
import org.apache.nutch.mapReduce.lib.IdentityReducer;
import org.apache.nutch.io.UTF8;
import org.apache.nutch.io.LongWritable;
import org.apache.nutch.io.WritableComparator;
import java.io.File;
import java.util.Random;
/* Extracts matching regexs from input files and counts them. */
public class Grep {
private Grep() {} // singleton
public static void main(String[] args) throws Exception {
if (args.length < 3) {
System.out.println("Grep <inDir> <outDir> <regex> [<group>]");
System.exit(-1);
}
File tempDir =
new File("grep-temp-"+
Integer.toString(new Random().nextInt(Integer.MAX_VALUE)));
JobConf grepJob = new JobConf();
grepJob.setNumMapTasks(18);
grepJob.setInputDir(new File(args[0]));
grepJob.setMapperClass(RegexMapper.class);
grepJob.set("mapred.mapper.regex", args[2]);
if (args.length == 4)
grepJob.set("mapred.mapper.regex.group", args[3]);
grepJob.setCombinerClass(LongSumReducer.class);
grepJob.setReducerClass(LongSumReducer.class);
grepJob.setNumReduceTasks(6);
grepJob.setOutputDir(tempDir);
grepJob.setOutputFormat(OutputFormats.get("seq"));
grepJob.setOutputKeyClass(UTF8.class);
grepJob.setOutputValueClass(LongWritable.class);
JobClient.runJob(grepJob);
JobConf sortJob = new JobConf();
sortJob.setNumMapTasks(6);
sortJob.setInputDir(tempDir);
sortJob.setInputFormat(InputFormats.get("seq"));
sortJob.setInputKeyClass(UTF8.class);
sortJob.setInputValueClass(LongWritable.class);
sortJob.setMapperClass(InverseMapper.class);
sortJob.setNumReduceTasks(1); // write a single file
sortJob.setOutputDir(new File(args[1]));
sortJob.setOutputKeyComparatorClass // sort by decreasing freq
(LongWritable.DecreasingComparator.class);
JobClient.runJob(sortJob);
new JobClient().getFs().delete(tempDir);
}
}