jdamasceno.hadoop.WordCount.java Source code

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Here is the source code for jdamasceno.hadoop.WordCount.java

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// WordCount.java
/*
 * Copyright 2010 10gen 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 jdamasceno.hadoop;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.bson.BSONObject;

import com.mongodb.hadoop.MongoInputFormat;
import com.mongodb.hadoop.MongoOutputFormat;
import com.mongodb.hadoop.util.MongoConfigUtil;

public class WordCount {

    public static class TokenizerMapper extends Mapper<Object, BSONObject, Text, IntWritable> {

        private final static IntWritable one = new IntWritable(1);
        private final Text word = new Text();

        public void map(Object key, BSONObject value, Context context) throws IOException, InterruptedException {

            //            System.out.println( "key: " + key );
            //            System.out.println( "value: " + value );

            final StringTokenizer itr = new StringTokenizer(value.get("message").toString());
            while (itr.hasMoreTokens()) {
                word.set(itr.nextToken());
                context.write(word, one);
            }
        }
    }

    public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {

        private final IntWritable result = new IntWritable();

        public void reduce(Text key, Iterable<IntWritable> values, Context context)
                throws IOException, InterruptedException {

            int sum = 0;
            for (final IntWritable val : values) {
                sum += val.get();
            }
            result.set(sum);
            context.write(key, result);
        }
    }

    public static void main(String[] args) throws Exception {

        final Configuration conf = new Configuration();
        MongoConfigUtil.setInputURI(conf, "mongodb://localhost/tweets.tweets");
        MongoConfigUtil.setOutputURI(conf, "mongodb://localhost/tweets.count");
        MongoConfigUtil.setSplitSize(conf, 4);

        System.out.println("Conf: " + conf);

        final Job job = new Job(conf, "word count");

        job.setJarByClass(WordCount.class);

        job.setMapperClass(TokenizerMapper.class);

        job.setCombinerClass(IntSumReducer.class);
        job.setReducerClass(IntSumReducer.class);

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

        job.setInputFormatClass(MongoInputFormat.class);
        job.setOutputFormatClass(MongoOutputFormat.class);

        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}