hadoop.org.apache.hadoop.mapreduce.lib.partition

Class InputSampler.IntervalSampler<K,V>

java.lang.Object

hadoop.org.apache.hadoop.mapreduce.lib.partition.InputSampler.IntervalSampler<K,V>

All Implemented Interfaces:

InputSampler.Sampler<K,V>

Enclosing class:

InputSampler<K,V>

public static class InputSampler.IntervalSampler<K,V>
extends Object
implements InputSampler.Sampler<K,V>

Sample from s splits at regular intervals. Useful for sorted data.

Constructor Summary

Constructors

Constructor and Description
IntervalSampler(double freq) Create a new IntervalSampler sampling all splits.
IntervalSampler(double freq, int maxSplitsSampled) Create a new IntervalSampler.

Method Summary

Modifier and Type	Method and Description
K[]	getSample(org.apache.hadoop.mapreduce.InputFormat<K,V> inf, org.apache.hadoop.mapreduce.Job job) For each split sampled, emit when the ratio of the number of records retained to the total record count is less than the specified frequency.

Methods inherited from class java.lang.Object

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

Constructor Detail

IntervalSampler

public IntervalSampler(double freq)

Create a new IntervalSampler sampling all splits.

Parameters:

freq - The frequency with which records will be emitted.

IntervalSampler

public IntervalSampler(double freq,
                       int maxSplitsSampled)

Create a new IntervalSampler.

Parameters:

freq - The frequency with which records will be emitted.

maxSplitsSampled - The maximum number of splits to examine.

See Also:

getSample(org.apache.hadoop.mapreduce.InputFormat<K, V>, org.apache.hadoop.mapreduce.Job)

Method Detail

getSample

public K[] getSample(org.apache.hadoop.mapreduce.InputFormat<K,V> inf,
                     org.apache.hadoop.mapreduce.Job job)
              throws IOException,
                     InterruptedException

For each split sampled, emit when the ratio of the number of records retained to the total record count is less than the specified frequency.

Specified by:

getSample in interface InputSampler.Sampler<K,V>

Throws:

IOException

InterruptedException