PrimeDivisor.java Source code

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Here is the source code for PrimeDivisor.java

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/**
 *  * 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 com.picc.test; 

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

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
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.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class PrimeDivisor {

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

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

        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            Text word = new Text();
            int num = 0;
            List<Integer> list = new ArrayList<Integer>();
            //value
            StringTokenizer itr = new StringTokenizer(value.toString());

            while (itr.hasMoreTokens()) {
                num = Integer.parseInt(itr.nextToken());
                list = DecompositionPrime(num);
                for (int i = 0; i < list.size(); i++) {
                    word.set(String.valueOf(list.get(i)));
                    IntWritable n = new IntWritable(num);
                    context.write(word, n);
                }
            }
        }

        private static List<Integer> DecompositionPrime(int num) {
            List<Integer> list = new ArrayList<Integer>();
            int i = 0;
            int k = num;

            while (true) {
                for (i = 2; i <= k; i++) {
                    if (k % i == 0) {
                        //i??
                        if (!list.contains(i))
                            list.add(i);
                        k = k / i;
                        break;
                    }
                }
                if (k == 1)
                    break;
            }
            return list;
        }
    }

    public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
        private IntWritable result = new IntWritable();

        public void reduce(Text key, Iterable<IntWritable> values, Context context)
                throws IOException, InterruptedException {
            int sum = 0;
            for (IntWritable val : values) {
                sum += val.get();
            }
            result.set(sum);
            context.write(key, result);
        }
    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
        if (otherArgs.length != 2) {
            System.err.println("Usage: wordcount <in> <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "word count");
        job.setJarByClass(PrimeDivisor.class);
        job.setMapperClass(TokenizerMapper.class);
        job.setCombinerClass(IntSumReducer.class);
        job.setReducerClass(IntSumReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}