org.apache.flink.runtime.operators

Class GroupReduceCombineDriver<T>

java.lang.Object

org.apache.flink.runtime.operators.GroupReduceCombineDriver<T>

Type Parameters:

T - The data type consumed and produced by the combiner.

All Implemented Interfaces:

PactDriver<FlatCombineFunction<T>,T>

public class GroupReduceCombineDriver<T>
extends Object
implements PactDriver<FlatCombineFunction<T>,T>

Combine operator, standalone (not chained)

The CombineTask uses a combining iterator over its input. The output of the iterator is emitted.

Constructor Summary

Constructors

Constructor and Description
GroupReduceCombineDriver()

Method Summary

Methods

Modifier and Type	Method and Description
void	cancel() This method is invoked when the driver must aborted in mid processing.
void	cleanup() This method is invoked in any case (clean termination and exception) at the end of the tasks operation.
int	getNumberOfInputs() Gets the number of inputs (= Nephele Gates and Readers) that the task has.
Class<FlatCombineFunction<T>>	getStubType() Gets the class of the stub type that is run by this task.
void	prepare() This method is called before the user code is opened.
boolean	requiresComparatorOnInput() Flag indicating whether the inputs require always comparators or not.
void	run() The main operation method of the task.
void	setup(PactTaskContext<FlatCombineFunction<T>,T> context)

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupReduceCombineDriver

public GroupReduceCombineDriver()

Method Detail

setup

public void setup(PactTaskContext<FlatCombineFunction<T>,T> context)

Specified by:

setup in interface PactDriver<FlatCombineFunction<T>,T>

getNumberOfInputs

public int getNumberOfInputs()

Description copied from interface: PactDriver

Gets the number of inputs (= Nephele Gates and Readers) that the task has.

Specified by:

getNumberOfInputs in interface PactDriver<FlatCombineFunction<T>,T>

Returns:

The number of inputs.

getStubType

public Class<FlatCombineFunction<T>> getStubType()

Description copied from interface: PactDriver

Gets the class of the stub type that is run by this task. For example, a MapTask should return MapFunction.class.

Specified by:

getStubType in interface PactDriver<FlatCombineFunction<T>,T>

Returns:

The class of the stub type run by the task.

requiresComparatorOnInput

public boolean requiresComparatorOnInput()

Description copied from interface: PactDriver

Flag indicating whether the inputs require always comparators or not.

Specified by:

requiresComparatorOnInput in interface PactDriver<FlatCombineFunction<T>,T>

Returns:

True, if the initialization should look for and create comparators, false otherwise.

prepare

public void prepare()
             throws Exception

Description copied from interface: PactDriver

This method is called before the user code is opened. An exception thrown by this method signals failure of the task.

Specified by:

prepare in interface PactDriver<FlatCombineFunction<T>,T>

Throws:

Exception - Exceptions may be forwarded and signal task failure.

run

public void run()
         throws Exception

Description copied from interface: PactDriver

The main operation method of the task. It should call the user code with the data subsets until the input is depleted.

Specified by:

run in interface PactDriver<FlatCombineFunction<T>,T>

Throws:

Exception - Any exception thrown by this method signals task failure. Because exceptions in the user code typically signal situations where this instance in unable to proceed, exceptions from the user code should be forwarded.

cleanup

public void cleanup()
             throws Exception

Description copied from interface: PactDriver

This method is invoked in any case (clean termination and exception) at the end of the tasks operation.

Specified by:

cleanup in interface PactDriver<FlatCombineFunction<T>,T>

Throws:

Exception - Exceptions may be forwarded.

cancel

public void cancel()

Description copied from interface: PactDriver

This method is invoked when the driver must aborted in mid processing. It is invoked asynchronously by a different thread.

Specified by:

cancel in interface PactDriver<FlatCombineFunction<T>,T>