| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.hadoop.examples; |
| |
| import java.util.Random; |
| |
| 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.LongWritable; |
| import org.apache.hadoop.io.Text; |
| import org.apache.hadoop.mapreduce.*; |
| import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; |
| import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat; |
| import org.apache.hadoop.mapreduce.lib.map.InverseMapper; |
| import org.apache.hadoop.mapreduce.lib.map.RegexMapper; |
| import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; |
| import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; |
| import org.apache.hadoop.mapreduce.lib.reduce.LongSumReducer; |
| import org.apache.hadoop.util.Tool; |
| import org.apache.hadoop.util.ToolRunner; |
| |
| /* Extracts matching regexs from input files and counts them. */ |
| public class Grep extends Configured implements Tool { |
| private Grep() {} // singleton |
| |
| public int run(String[] args) throws Exception { |
| if (args.length < 3) { |
| System.out.println("Grep <inDir> <outDir> <regex> [<group>]"); |
| ToolRunner.printGenericCommandUsage(System.out); |
| return 2; |
| } |
| |
| Path tempDir = |
| new Path("grep-temp-"+ |
| Integer.toString(new Random().nextInt(Integer.MAX_VALUE))); |
| |
| Configuration conf = getConf(); |
| conf.set(RegexMapper.PATTERN, args[2]); |
| if (args.length == 4) |
| conf.set(RegexMapper.GROUP, args[3]); |
| |
| Job grepJob = new Job(conf); |
| |
| try { |
| |
| grepJob.setJobName("grep-search"); |
| |
| FileInputFormat.setInputPaths(grepJob, args[0]); |
| |
| grepJob.setMapperClass(RegexMapper.class); |
| |
| grepJob.setCombinerClass(LongSumReducer.class); |
| grepJob.setReducerClass(LongSumReducer.class); |
| |
| FileOutputFormat.setOutputPath(grepJob, tempDir); |
| grepJob.setOutputFormatClass(SequenceFileOutputFormat.class); |
| grepJob.setOutputKeyClass(Text.class); |
| grepJob.setOutputValueClass(LongWritable.class); |
| |
| grepJob.waitForCompletion(true); |
| |
| Job sortJob = new Job(conf); |
| sortJob.setJobName("grep-sort"); |
| |
| FileInputFormat.setInputPaths(sortJob, tempDir); |
| sortJob.setInputFormatClass(SequenceFileInputFormat.class); |
| |
| sortJob.setMapperClass(InverseMapper.class); |
| |
| sortJob.setNumReduceTasks(1); // write a single file |
| FileOutputFormat.setOutputPath(sortJob, new Path(args[1])); |
| sortJob.setSortComparatorClass( // sort by decreasing freq |
| LongWritable.DecreasingComparator.class); |
| |
| sortJob.waitForCompletion(true); |
| } |
| finally { |
| FileSystem.get(conf).delete(tempDir, true); |
| } |
| return 0; |
| } |
| |
| public static void main(String[] args) throws Exception { |
| int res = ToolRunner.run(new Configuration(), new Grep(), args); |
| System.exit(res); |
| } |
| |
| } |