InputSamplerMapper.java Source code

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Here is the source code for InputSamplerMapper.java

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/*
 * 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.BufferedInputStream;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.Random;

import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.MapWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.util.ReflectionUtils;

public class InputSamplerMapper extends MapReduceBase implements Mapper<LongWritable, Text, IntWritable, Text> {
    private int id;
    private MapWritable map;

    @Override
    public void configure(JobConf conf) {
        id = conf.getInt("mapred.task.partition", -1);
        try {
            map = new MapWritable();
            Path[] localFiles = DistributedCache.getLocalCacheFiles(conf);
            BufferedInputStream in = new BufferedInputStream(new FileInputStream(localFiles[0].toString()));
            map.readFields(new DataInputStream(in));
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }
    }

    @Override
    public void map(LongWritable key, Text value, OutputCollector<IntWritable, Text> output, Reporter reporter)
            throws IOException {
        reporter.incrCounter("FIMMapperStart", String.valueOf(id), System.currentTimeMillis());
        IntArrayWritable arr = (IntArrayWritable) map.get(key);
        if (arr != null) {
            for (Writable element : arr.get()) {
                output.collect((IntWritable) element, value);
            }
        }
        reporter.incrCounter("FIMMapperEnd", String.valueOf(id), System.currentTimeMillis());
    }
}