de.gerdiproject.harvest.event

Class EventSystem

java.lang.Object

de.gerdiproject.harvest.event.EventSystem

public final class EventSystem
extends Object

This singleton class provides a means to dispatch and listen to IEvents.

Author:

Robin Weiss

Method Summary

Modifier and Type	Method and Description
static <T extends IEvent> void	addListener(Class<T> eventClass, Consumer<T> callback) Adds a callback function that is to be executed when a specified event is dispatched.
static <R,T extends ISynchronousEvent<R>> void	addSynchronousListener(Class<T> eventClass, Function<T,R> callback) Adds a callback function that executes and returns a value when a specified synchronous event is dispatched.
static <R,T extends ISynchronousEvent<R>> void	addSynchronousListener(Class<T> eventClass, Supplier<R> callback) Adds a callback function that executes and returns a value when a specified synchronous event is dispatched.
static boolean	hasAsynchronousEventListeners() Checks if there are registered event listeners.
static boolean	hasSynchronousEventListeners() Checks if there are registered synchronous event listeners.
static <T extends IEvent> void	removeAllListeners(Class<T> eventClass) Removes all event listeners of a specified event.
static <T extends IEvent> void	removeListener(Class<T> eventClass, Consumer<T> callback) Removes a callback function for a specified event.
static <T extends ISynchronousEvent<?>> void	removeSynchronousListener(Class<T> eventClass) Removes the callback function of a synchronous event.
static void	reset() Removes all listeners and clears the queue.
static <T extends IEvent> void	sendEvent(T event) Dispatches a specified asynchronous event by adding it to a queue.
static <R,T extends ISynchronousEvent<R>> R	sendSynchronousEvent(T event) Dispatches a synchronous event that executes a unique callback function and returns its calculated value.

Methods inherited from class java.lang.Object

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

Method Detail

addListener

public static <T extends IEvent> void addListener(Class<T> eventClass,
                                                  Consumer<T> callback)

Adds a callback function that is to be executed when a specified event is dispatched.

Type Parameters:

T - the type of the event

Parameters:

eventClass - the class of the event

callback - the callback function that is executed when the event is dispatched

removeListener

public static <T extends IEvent> void removeListener(Class<T> eventClass,
                                                     Consumer<T> callback)

Removes a callback function for a specified event.

Type Parameters:

T - the type of the event

Parameters:

eventClass - the class of the event

callback - the callback function that is to be removed from the event

removeAllListeners

public static <T extends IEvent> void removeAllListeners(Class<T> eventClass)

Removes all event listeners of a specified event.

Type Parameters:

T - the type of the event

Parameters:

eventClass - the class of the event

reset

public static void reset()

Removes all listeners and clears the queue.

sendEvent

public static <T extends IEvent> void sendEvent(T event)

Dispatches a specified asynchronous event by adding it to a queue. If the event is the only one in the queue, its callback functions will be called immediately. Otherwise, all other queued events will be processed first.

Type Parameters:

T - the type of the dispatched event

Parameters:

event - the event that is dispatched

addSynchronousListener

public static <R,T extends ISynchronousEvent<R>> void addSynchronousListener(Class<T> eventClass,
                                                                             Function<T,R> callback)

Adds a callback function that executes and returns a value when a specified synchronous event is dispatched. Due to the synchronous nature, only one callback function may be registered per event class.

Type Parameters:

T - the type of the synchronous event

R - the type of the return value of the callback function

Parameters:

eventClass - the class of the synchronous event

callback - a callback function that requires the event as a parameter and returns a specified value when the event is dispatched

addSynchronousListener

public static <R,T extends ISynchronousEvent<R>> void addSynchronousListener(Class<T> eventClass,
                                                                             Supplier<R> callback)

Adds a callback function that executes and returns a value when a specified synchronous event is dispatched. Due to the synchronous nature, only one callback function may be registered per event class.

Type Parameters:

T - the type of the synchronous event

R - the type of the return value of the callback function

Parameters:

eventClass - the class of the synchronous event

callback - a callback function that expects no parameters and returns when the event is dispatched

removeSynchronousListener

public static <T extends ISynchronousEvent<?>> void removeSynchronousListener(Class<T> eventClass)

Removes the callback function of a synchronous event.

Type Parameters:

T - the type of the synchronous event

Parameters:

eventClass - the class of the synchronous event

sendSynchronousEvent

public static <R,T extends ISynchronousEvent<R>> R sendSynchronousEvent(T event)

Dispatches a synchronous event that executes a unique callback function and returns its calculated value.

Type Parameters:

T - the type of the synchronous event

R - the type of the return value of the callback function

Parameters:

event - a synchronous event

Returns:

the return value of the callback function that is registered

hasAsynchronousEventListeners

public static boolean hasAsynchronousEventListeners()

Checks if there are registered event listeners.

Returns:

true if there is at least one registered IEvent

hasSynchronousEventListeners

public static boolean hasSynchronousEventListeners()

Checks if there are registered synchronous event listeners.

Returns:

true if there is at least one registered ISynchronousEvent