FIMReducer.java Source code

Introduction

Here is the source code for FIMReducer.java

Source

/*
 * Copyright 2012-14 Justin A. Debrabant <debrabant@cs.brown.edu> and Matteo Riondato <matteo@cs.brown.edu>
 *
 * 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.
 *
 */

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Random;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;

import fim.fpgrowth.*;

public class FIMReducer extends MapReduceBase implements Reducer<IntWritable, Text, Text, DoubleWritable> {
    private int minFreqPercent;
    private int sampleSize;
    private int id;
    private float epsilon;
    private boolean set;

    @Override
    public void configure(JobConf conf) {
        minFreqPercent = conf.getInt("PARMM.minFreqPercent", 20);
        sampleSize = conf.getInt("PARMM.sampleSize", 1000);
        epsilon = conf.getFloat("PARMM.epsilon", 0.05f);
        id = conf.getInt("mapred.task.partition", -1);
        set = false;
    }

    @Override
    public void reduce(IntWritable key, Iterator<Text> values, OutputCollector<Text, DoubleWritable> output,
            Reporter reporter) throws IOException {
        long startTime = System.currentTimeMillis();
        if (!set) {
            reporter.incrCounter("FIMReducerStart", String.valueOf(id), startTime);
            reporter.incrCounter("FIMReducerEnd", String.valueOf(id), startTime);
            set = true;
        }

        // This is a very crappy way of checking whether we got the
        // right number of transactions. It may not be too inefficient
        // though.
        ArrayList<Text> transactions = new ArrayList<Text>(sampleSize);
        while (values.hasNext()) {
            Text trans = new Text(values.next().toString());
            transactions.add(trans);
        }
        if (sampleSize != transactions.size()) {
            System.out.println("WRONG NUMBER OF TRANSACTIONS!");
        }
        System.out.println("samplesize: " + sampleSize + " received: " + transactions.size());
        FPgrowth.mineFrequentItemsets(transactions.iterator(), transactions.size(), minFreqPercent - (epsilon * 50),
                output);

        long endTime = System.currentTimeMillis();
        reporter.incrCounter("FIMReducerEnd", String.valueOf(id), endTime - startTime);
    }
}