package org.hackreduce.mappers.ngram;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.hackreduce.mappers.ModelMapper;
import org.hackreduce.models.ngram.TwoGram;
/**
* Extends the basic Hadoop {@link Mapper} to process the 2gram data dump by
* accessing {@link TwoGram}
*
* @param <K> Output class of the mapper key
* @param <V> Output class of the mapper value
*
*/
public abstract class TwoGramMapper<K extends WritableComparable<?>, V extends Writable>
extends ModelMapper<TwoGram, LongWritable, Text, K, V> {
/**
* Configures the MapReduce job to read data from the NASDAQ dump from Infochimps.
*
* @param job
*/
public static void configureJob(Job job) {
job.setInputFormatClass(TextInputFormat.class);
}
@Override
protected TwoGram instantiateModel(LongWritable key, Text value) {
return new TwoGram(value);
}
}