com.pagerankcalculator.calculation.PageRankCalculationMapper.java Source code

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Here is the source code for com.pagerankcalculator.calculation.PageRankCalculationMapper.java

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package com.pagerankcalculator.calculation;

import com.pagerankcalculator.TwitterPageRank;
import java.io.IOException;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

/**
 *
 * @author mfikria
 */
public class PageRankCalculationMapper extends Mapper<LongWritable, Text, Text, Text> {

    @Override
    public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {

        int tabIdx1 = value.find("\t");
        int tabIdx2 = value.find("\t", tabIdx1 + 1);

        String userID = Text.decode(value.getBytes(), 0, tabIdx1);
        String pageRank = Text.decode(value.getBytes(), tabIdx1 + 1, tabIdx2 - (tabIdx1 + 1));
        String CSVFollowingIDs = Text.decode(value.getBytes(), tabIdx2 + 1, value.getLength() - (tabIdx2 + 1));

        //        System.out.print(userID);
        //        System.out.print("\t");
        //        System.out.print(pageRank);
        //        System.out.print("\t");
        //        System.out.println(CSVFollowingIDs);

        String[] followingIDs = CSVFollowingIDs.split(TwitterPageRank.FOLLOWING_LIST_DELIMETER);
        Integer totalFollowingIDs = followingIDs.length;
        for (String followingID : followingIDs) {
            String pageRankWithTotalFollowing = pageRank + "\t" + totalFollowingIDs.toString();

            context.write(new Text(followingID), new Text(pageRankWithTotalFollowing));
        }

        context.write(new Text(userID), new Text(TwitterPageRank.FOLLOWING_LIST_TAG + CSVFollowingIDs));
    }

}