edu.purdue.cs.eblanton
Class CounterReduce

java.lang.Object
  org.apache.hadoop.mapred.MapReduceBase
      edu.purdue.cs.eblanton.CounterReduce

All Implemented Interfaces:

java.io.Closeable, org.apache.hadoop.mapred.JobConfigurable, org.apache.hadoop.mapred.Reducer<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable,org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable>

public class CounterReduce
extends org.apache.hadoop.mapred.MapReduceBase
implements org.apache.hadoop.mapred.Reducer<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable,org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable>

CounterReduce implements a reduction which accepts any WritableComparable object and a vector of IntWritable occurrence counts, and sums these counts.

See Also:

MapReduceBase, Reducer

Constructor Summary

CounterReduce()

Method Summary

void

reduce(org.apache.hadoop.io.WritableComparable key, java.util.Iterator<org.apache.hadoop.io.IntWritable> values, org.apache.hadoop.mapred.OutputCollector<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable> output, org.apache.hadoop.mapred.Reporter reporter) Implements the CounterReduce reduction operation.

Methods inherited from class org.apache.hadoop.mapred.MapReduceBase

close, configure

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.mapred.JobConfigurable

configure

Methods inherited from interface java.io.Closeable

close

Constructor Detail

CounterReduce

public CounterReduce()

Method Detail

reduce

public void reduce(org.apache.hadoop.io.WritableComparable key,
                   java.util.Iterator<org.apache.hadoop.io.IntWritable> values,
                   org.apache.hadoop.mapred.OutputCollector<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable> output,
                   org.apache.hadoop.mapred.Reporter reporter)
            throws java.io.IOException

Implements the CounterReduce reduction operation.

Specified by:

reduce in interface org.apache.hadoop.mapred.Reducer<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable,org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.IntWritable>

Parameters:

key - the WritableComparable object being counted

values - iterator over counts provided by the Map operation

output - the output collector for the resulting sum

reporter - ignored

Throws:

java.io.IOException