org.apache.reef.runtime.common.utils

Class DispatchingEStage

java.lang.Object

org.apache.reef.runtime.common.utils.DispatchingEStage

All Implemented Interfaces:

AutoCloseable

public final class DispatchingEStage
extends Object
implements AutoCloseable

Delayed event router that dispatches messages to the proper event handler by type. This class is used in EvaluatorManager to isolate user threads from REEF.

Constructor Summary

Constructors

Constructor and Description
DispatchingEStage(DispatchingEStage other) Constructs a DispatchingEStage that uses the Thread pool and ErrorHandler of another one.
DispatchingEStage(EventHandler<Throwable> errorHandler, int numThreads, String stageName)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the stage adn stop accepting new messages.
boolean	isClosed() Check if the stage can still accept messages.
boolean	isEmpty() Return true if there are no messages queued or in processing, false otherwise.
<T,U extends T> void	onNext(Class<T> type, U message) Dispatch a new message by type.
<T,U extends T> void	register(Class<T> type, Set<EventHandler<U>> handlers) Register a new event handler.

Methods inherited from class java.lang.Object

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

Constructor Detail

DispatchingEStage

public DispatchingEStage(EventHandler<Throwable> errorHandler,
                 int numThreads,
                 String stageName)

Parameters:

errorHandler - used for exceptions thrown from the event handlers registered.

numThreads - number of threads to allocate to dispatch events.

stageName - the name to use for the underlying stage. It will be carried over to name the Thread(s) spawned.

DispatchingEStage

public DispatchingEStage(DispatchingEStage other)

Constructs a DispatchingEStage that uses the Thread pool and ErrorHandler of another one.

Parameters:

other -

Method Detail

register

public <T,U extends T> void register(Class<T> type,
                            Set<EventHandler<U>> handlers)

Register a new event handler.

Type Parameters:

T - Message type.

U - Type of message that event handler supports. Must be a subclass of T.

Parameters:

type - Message type to process with this handler.

handlers - A set of handlers that process that type of message.

onNext

public <T,U extends T> void onNext(Class<T> type,
                          U message)

Dispatch a new message by type. If the stage is already closed, log a warning and ignore the message.

Type Parameters:

T - Message type that event handler supports.

U - input message type. Must be a subclass of T.

Parameters:

type - Type of event handler - must match the register() call.

message - A message to process. Must be a subclass of T.

isEmpty

public boolean isEmpty()

Return true if there are no messages queued or in processing, false otherwise.

close

public void close()

Close the stage adn stop accepting new messages. Closes the internal thread pool.

Specified by:

close in interface AutoCloseable

isClosed

public boolean isClosed()

Check if the stage can still accept messages.

Returns:

true if the stage can no longer accept messages, false otherwise.