br.com.lassal.nqueens.grid.mapreduce.NQueenIncrementalCounterResultReducer.java Source code

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Here is the source code for br.com.lassal.nqueens.grid.mapreduce.NQueenIncrementalCounterResultReducer.java

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package br.com.lassal.nqueens.grid.mapreduce;

import java.math.BigInteger;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

/**
 *
 * @author Lucalves33
 */
public class NQueenIncrementalCounterResultReducer extends Reducer<Text, Text, NullWritable, Text> {

    protected void reduce(Text key, Iterable<Text> values, Context context)
            throws java.io.IOException, InterruptedException {
        BigInteger partialCount = BigInteger.ZERO;
        long numPartialSolutions = 0;

        for (Text item : values) {
            String value = item.toString();

            if (NQueenIncrementalCounterResultMapper.PARTIAL_SOLUTION_ID.equals(value)
                    && numPartialSolutions < Long.MAX_VALUE) {
                numPartialSolutions++;
            } else {
                BigInteger solutionCount = new BigInteger(value);
                partialCount = partialCount.add(solutionCount);
            }
        }

        context.write(NullWritable.get(), new Text(key.toString() + "=" + partialCount.toString() + ";"));

        if (numPartialSolutions > 0) {
            context.write(NullWritable.get(), new Text(
                    key.toString() + " NO FINALIZADO - EXISTEM " + numPartialSolutions + " SOLUES ABERTAS."));
        }
    }
}