Module javafx.base

Package javafx.event

Interface EventDispatchChain

public interface EventDispatchChain

Represents a chain of EventDispatcher objects, which can dispatch an Event. The event is dispatched by passing it from one EventDispatcher to the next in the chain until the end of chain is reached. Each EventDispatcher in the chain can influence the event path and the event itself. The chain is usually formed by following some parent - child hierarchy from the root to the event target and appending all EventDispatcher objects encountered to the chain.

Since:

JavaFX 2.0

Method Summary

Modifier and Type	Method	Description
EventDispatchChain	append(EventDispatcher eventDispatcher)	Appends the specified EventDispatcher to this chain.
Event	dispatchEvent(Event event)	Dispatches the specified event through this EventDispatchChain.
EventDispatchChain	prepend(EventDispatcher eventDispatcher)	Prepends the specified EventDispatcher to this chain.

Method Details

append

EventDispatchChain append(EventDispatcher eventDispatcher)

Appends the specified EventDispatcher to this chain. Returns a reference to the chain with the appended element.

The caller shouldn't assume that this EventDispatchChain remains unchanged nor that the returned value will reference a different chain after the call. All this depends on the EventDispatchChain implementation.

So the call should be always done in the following form: chain = chain.append(eventDispatcher);

Parameters:

eventDispatcher - the EventDispatcher to append to the chain

Returns:

the chain with the appended event dispatcher

prepend

EventDispatchChain prepend(EventDispatcher eventDispatcher)

Prepends the specified EventDispatcher to this chain. Returns a reference to the chain with the prepended element.

The caller shouldn't assume that this EventDispatchChain remains unchanged nor that the returned value will reference a different chain after the call. All this depends on the EventDispatchChain implementation.

So the call should be always done in the following form: chain = chain.prepend(eventDispatcher);

Parameters:

eventDispatcher - the EventDispatcher to prepend to the chain

Returns:

the chain with the prepended event dispatcher

dispatchEvent

Event dispatchEvent(Event event)

Dispatches the specified event through this EventDispatchChain. The return value represents the event after processing done by the chain. If further processing is to be done after the call the event referenced by the return value should be used instead of the original event. In the case the event is fully handled / consumed in the chain the returned value is null and no further processing should be done with that event.

Parameters:

event - the event to dispatch

Returns:

the processed event or null if the event had been fully handled / consumed