de.skuzzle.jeve

Interface EventStack

public interface EventStack

Stack class which is used to keep track of currently dispatched Events. Before an Event is being dispatched, it is pushed onto this stack and right after it has been dispatched to all listeners it is popped off again. This allows queries such as which events are currently active.

Implementations must be thread safe.

Author:

Simon Taddiken

Method Summary

Modifier and Type	Method and Description
void	dumpStack() Prints the current event stack to the log using SLF4j log level debug.
void	dumpStack(PrintStream out) Prints the current event stack to the provided PrintStream.
boolean	isActive(Class<? extends Listener> listenerClass) Determines whether an Event is being dispatched for the given listener class.
boolean	isActive(Event<?,?> event) Determines whether an Event for the same listener class as the given one's is currently being dispatched.
boolean	isAnyActive(Collection<? extends Class<? extends Listener>> c) Determines whether an Event is being dispatched for at least one listener class contained in the given collection.
Optional<Event<?,?>>	peek() Returns the head element of the current stack if there is any.
Optional<SequentialEvent<?,?>>	preventDispatch(Class<? extends Listener> listenerClass) Checks whether dispatch for events with the given event should be prevented.
Optional<SequentialEvent<?,?>>	preventDispatch(Event<?,?> event) Checks whether dispatch of the given event should be prevented.

Method Detail

dumpStack

void dumpStack()

Prints the current event stack to the log using SLF4j log level debug.

dumpStack

void dumpStack(PrintStream out)

Prints the current event stack to the provided PrintStream.

Parameters:

out - The stream to print the log to.

peek

Optional<Event<?,?>> peek()

Returns the head element of the current stack if there is any.

Returns:

The top of the event stack.

isActive

boolean isActive(Event<?,?> event)

Determines whether an Event for the same listener class as the given one's is currently being dispatched.

Parameters:

event - The event to retrieve the listener class from.

Returns:

Whether an Event for the same listener class is already being dispatched.

isAnyActive

boolean isAnyActive(Collection<? extends Class<? extends Listener>> c)

Determines whether an Event is being dispatched for at least one listener class contained in the given collection.

Parameters:

c - Collection of listener classes.

Returns:

Whether an Event for at least one class from c is already being dispatched.

isActive

boolean isActive(Class<? extends Listener> listenerClass)

Determines whether an Event is being dispatched for the given listener class.

Parameters:

listenerClass - The listener class to check for.

Returns:

Whether an Event for the given listener class is already being dispatched.

preventDispatch

Optional<SequentialEvent<?,?>> preventDispatch(Event<?,?> event)

Checks whether dispatch of the given event should be prevented. This is the case if there is at least one SequentialEvent currently being dispatched, on which SequentialEvent.preventCascade(Class) has been called with the given event's listener class.

Parameters:

event - The event to check whether it should be prevented.

Returns:

If present, the optional holds the SequentialEvent which prevented the given one. If not present, the given event should not be prevented.

See Also:

EventStackHelper.checkPrevent(EventStack, Event, java.util.function.BiConsumer, ExceptionCallback)

preventDispatch

Optional<SequentialEvent<?,?>> preventDispatch(Class<? extends Listener> listenerClass)

Checks whether dispatch for events with the given event should be prevented. This is the case if there is at least one SequentialEvent currently being dispatched, on which SequentialEvent.preventCascade(Class) has been called with the given listener class.

Parameters:

listenerClass - The listener class to check for.

Returns:

If present, the optional holds the SequentialEvent which prevents dispatch of the given listener class. If not present, events should not be prevented for the given class.

See Also:

EventStackHelper.checkPrevent(EventStack, Event, java.util.function.BiConsumer, ExceptionCallback)