org.apache.flink.api.java.functions

Class SampleInCoordinator<T>

java.lang.Object

org.apache.flink.api.java.functions.SampleInCoordinator<T>

Type Parameters:

T - the data type wrapped in ElementWithRandom as input.

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.GroupReduceFunction<IntermediateSampleData<T>,T>

@Internal
public class SampleInCoordinator<T>
extends Object
implements org.apache.flink.api.common.functions.GroupReduceFunction<IntermediateSampleData<T>,T>

SampleInCoordinator wraps the sample logic of the coordinator side (the second phase of distributed sample algorithm). It executes the coordinator side sample logic in an all reduce function. The user needs to make sure that the operator parallelism of this function is 1 to make sure this is a central coordinator. Besides, we do not need the task index information for random generator seed as the parallelism must be 1.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SampleInCoordinator(boolean withReplacement, int numSample, long seed) Create a function instance of SampleInCoordinator.

Method Summary

Modifier and Type	Method and Description
void	reduce(Iterable<IntermediateSampleData<T>> values, org.apache.flink.util.Collector<T> out)

Methods inherited from class java.lang.Object

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

Constructor Detail

SampleInCoordinator

public SampleInCoordinator(boolean withReplacement,
                           int numSample,
                           long seed)

Create a function instance of SampleInCoordinator.

Parameters:

withReplacement - Whether element can be selected more than once.

numSample - Fixed sample size.

seed - Random generator seed.

Method Detail

reduce

public void reduce(Iterable<IntermediateSampleData<T>> values,
                   org.apache.flink.util.Collector<T> out)
            throws Exception

Specified by:

reduce in interface org.apache.flink.api.common.functions.GroupReduceFunction<IntermediateSampleData<T>,T>

Throws:

Exception