com.cloudera.recordservice.examples.mapreduce.WordCount.java Source code

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Here is the source code for com.cloudera.recordservice.examples.mapreduce.WordCount.java

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// Copyright 2014 Cloudera Inc.
//
// 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 com.cloudera.recordservice.examples.mapreduce;

import java.io.IOException;
import java.util.Iterator;
import java.util.StringTokenizer;

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.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;

import com.cloudera.recordservice.mr.RecordServiceConfig;

/**
 * To run the program:
 * hadoop jar recordservice-examples-*.jar \
 * com.cloudera.recordservice.examples.mapreduce.WordCount <input path> <output path>
 *
 * Append false in the command to run WordCount without RecordService
 */
public class WordCount {
    public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {
        private final static IntWritable one = new IntWritable(1);
        private Text word = new Text();

        @Override
        public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter)
                throws IOException {
            String line = value.toString();
            StringTokenizer tokenizer = new StringTokenizer(line);
            while (tokenizer.hasMoreTokens()) {
                word.set(tokenizer.nextToken());
                output.collect(word, one);
            }
        }
    }

    public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> {
        @Override
        public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output,
                Reporter reporter) throws IOException {
            int sum = 0;
            while (values.hasNext()) {
                sum += values.next().get();
            }
            output.collect(key, new IntWritable(sum));
        }
    }

    public void run(String[] args) throws Exception {
        boolean useRecordService = true;
        if (args.length == 3) {
            useRecordService = Boolean.parseBoolean(args[2]);
        } else if (args.length != 2) {
            System.err.println("Usage: WordCount <input path> <output path>");
            System.exit(-1);
        }
        String input = args[0].trim();
        String output = args[1];

        JobConf conf = new JobConf(WordCount.class);
        conf.setJobName("wordcount-" + (useRecordService ? "with" : "without") + "-RecordService");

        conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(IntWritable.class);

        conf.setMapperClass(Map.class);
        conf.setCombinerClass(Reduce.class);
        conf.setReducerClass(Reduce.class);

        if (useRecordService) {
            conf.setInputFormat(com.cloudera.recordservice.mapred.TextInputFormat.class);
            RecordServiceConfig.setInput(conf, input);
        } else {
            conf.setInputFormat(TextInputFormat.class);
            FileInputFormat.setInputPaths(conf, new Path(input));
        }

        FileSystem fs = FileSystem.get(conf);
        Path outputPath = new Path(output);
        if (fs.exists(outputPath))
            fs.delete(outputPath, true);
        conf.setOutputFormat(TextOutputFormat.class);
        FileOutputFormat.setOutputPath(conf, outputPath);

        JobClient.runJob(conf);
        System.out.println("Done");
    }

    public static void main(String[] args) throws Exception {
        new WordCount().run(args);
    }
}