net.openhft.chronicle.core.threads

Interface EventHandler

All Superinterfaces:

VanillaEventHandler

All Known Implementing Classes:

CancellableTimer.ScheduledEventHandler

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface EventHandler
extends VanillaEventHandler

Represents a handler for events within an event loop.

This interface should be implemented by classes that handle specific events within an event loop.

An EventHandler can be registered to an EventLoop for processing events.

Method Summary

Modifier and Type	Method and Description
default void	eventLoop(EventLoop eventLoop) This method is called once when it is added to an eventLoop, which might be before the EventLoop has started This could be called in any thread.
default void	loopFinished() Notify handler that the event handler's action method will not be called again.
default void	loopStarted() This handler has begun being executed on the event loop.
default @NotNull HandlerPriority	priority() Returns the priority level of this event handler within the event loop.

Methods inherited from interface net.openhft.chronicle.core.threads.VanillaEventHandler

action

Method Detail

eventLoop

default void eventLoop(EventLoop eventLoop)

This method is called once when it is added to an eventLoop, which might be before the EventLoop has started This could be called in any thread.

Parameters:

eventLoop - The event loop to which this handler has been added.

loopStarted

default void loopStarted()

This handler has begun being executed on the event loop. This will be called after the call to eventLoop(EventLoop) and will always be called on the EventLoop thread.

This call will be followed by zero or more invocations of VanillaEventHandler.action() and then an invocation of loopFinished()

Exceptions thrown by loopStarted will be logged and the handler will be removed from the event loop.

loopFinished

default void loopFinished()

Notify handler that the event handler's action method will not be called again. It will be called if and only if loopStarted() was called, and will always be called on the event loop thread.

This is called either when the event loop is terminating, or if this EventHandler is being removed from the event loop.

If this handler implements Closeable then the event loop will call close (once only) on this after loopFinished has been called.

loopFinished is the place to put any clean-up that MUST be performed on the event loop thread, or cleanup that only needs to occur if loopStarted() was called. All other clean up can be put into Closeable.close().

Exceptions thrown by loopFinished or close are caught and logged (at warning level) and cleanup continues.

priority

@NotNull
default @NotNull HandlerPriority priority()

Returns the priority level of this event handler within the event loop.

Returns:

The priority level of this event handler.