Inlinks.java Source code

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Here is the source code for Inlinks.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 org.apache.hadoop.examples;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

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 Inlinks {

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

        private static IntWritable mkey = new IntWritable();
        private static IntWritable mval = new IntWritable();

        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            //ArrayList<String> details = CSVParser.parseLine(value.toString());
            String[] parts = value.toString().split("[ ,]");
            mval.set(Integer.parseInt(parts[0]));
            mkey.set(Integer.parseInt(parts[1]));
            context.write(mkey, mval);
        }
    }

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

        Text value = new Text();

        public void reduce(IntWritable key, Iterable<IntWritable> values, Context context)
                throws IOException, InterruptedException {
            StringBuilder sb = new StringBuilder("");
            for (IntWritable val : values) {
                sb.append(Integer.toString(val.get()) + " ");
            }
            value.set(sb.toString());
            context.write(key, value);
        }

    }

    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: inlinks <in> [<in>...] <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "inlinks");
        job.setJarByClass(Inlinks.class);
        job.setMapperClass(TokenizerMapper.class);
        //job.setCombinerClass(IdentityReducer.class);
        job.setReducerClass(IdentityReducer.class);
        job.setNumReduceTasks(10);
        job.setOutputKeyClass(IntWritable.class);
        job.setOutputValueClass(IntWritable.class);
        for (int i = 0; i < otherArgs.length - 1; ++i) {
            FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
        }
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[otherArgs.length - 1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}