myGrep.Grep.java Source code

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Here is the source code for myGrep.Grep.java

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package myGrep;

import java.io.IOException;

/**
 * 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.
 */

import java.util.Random;
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.FSDataOutputStream;
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.Mapper.Context;
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 static FSDataOutputStream osLog;
    private static Configuration conf_log;

    private static FileSystem hdfs_log;

    private static Path dfs_log;

    private Grep() {
    } // singleton

    public static int init_log() throws Exception {
        conf_log = new Configuration();

        hdfs_log = FileSystem.get(conf_log);

        dfs_log = new Path("/user/ubt/WordCount/log");

        osLog = hdfs_log.create(dfs_log);
        return 0;
    }

    public static int write_log(String log) throws Exception {
        osLog.writeChars(log);
        return 0;
    }

    public static class myRegMapper<K> extends Mapper<K, Text, Text, LongWritable> {
        public static String PATTERN = "mapreduce.mapper.regex";
        public static String GROUP = "mapreduce.mapper.regexmapper..group";
        private Pattern pattern;
        private int group;

        public void setup(Context context) {
            Configuration conf = context.getConfiguration();
            pattern = Pattern.compile(conf.get(PATTERN));
            group = conf.getInt(GROUP, 0);
        }

        public void map(K key, Text value, Context context) throws IOException, InterruptedException {
            String text = value.toString();
            Matcher matcher = pattern.matcher(text);
            while (matcher.find()) {
                try {
                    System.out.println(matcher.group(group));
                    //this is reg get.
                    //write_log( matcher.group(group) );
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                context.write(new Text(matcher.group(group)), new LongWritable(1));
            }
        }
    }

    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;
        }
        System.out.println("0:" + args[0] + " 1:" + args[1] + " 2:" + args[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 = Job.getInstance(conf);

        try {
            init_log();

            grepJob.setJobName("wzl-grep-search");
            grepJob.setJarByClass(Grep.class);

            FileInputFormat.setInputPaths(grepJob, args[0]);

            //grepJob.setMapperClass(RegexMapper.class);
            grepJob.setMapperClass(myRegMapper.class);

            //(string, int) -> sub int -> (string , sum)
            grepJob.setCombinerClass(LongSumReducer.class);
            grepJob.setReducerClass(LongSumReducer.class);

            //FileOutputFormat.setOutputPath(grepJob, tempDir);
            FileOutputFormat.setOutputPath(grepJob, new Path(args[1]));
            grepJob.setOutputFormatClass(SequenceFileOutputFormat.class);
            grepJob.setOutputKeyClass(Text.class);
            grepJob.setOutputValueClass(LongWritable.class);

            grepJob.waitForCompletion(true);

            /*
                
            Job sortJob = Job.getInstance(conf);
            sortJob.setJobName("wzl-grep-sort");
            sortJob.setJarByClass(Grep.class);
                
            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);
    }

}