com.sun.javafx.event.EventRedirector Maven / Gradle / Ivy
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* published by the Free Software Foundation. Oracle designates this
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* by Oracle in the LICENSE file that accompanied this code.
*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package com.sun.javafx.event;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import javafx.event.Event;
import javafx.event.EventDispatcher;
import javafx.event.EventType;
/**
* This event dispatcher redirects received events to the registered child
* dispatchers before dispatching them to the rest of the dispatch chain. The
* redirected events are wrapped in {@code RedirectedEvent} instances, so they
* can be easily recognized from normal direct events. If an original event
* wrapped in the {@code RedirectedEvent} is consumed by any of the child
* dispatchers, it won't be sent by the {@code EventRedirector} to the rest of
* the original dispatch chain.
*
* The child dispatchers can also be instances of {@code EventRedirector} and
* might receive both, the normal events (from other sources) and the redirected
* events from the parent {@code EventRedirector}. If a {@code RedirectedEvent}
* is received, it is forwarded to the child event dispatchers without any
* additional wrapping.
*
* For this hierarchical arrangement of {@code EventRedirector} instances the
* class defines the {@code handleRedirectedEvent} method, which is called with
* a received redirected event, after the event has been forwarded to the child
* dispatchers. By default this method is empty, but can be overridden in
* derived classes to define specific handling of these redirected events.
*/
public class EventRedirector extends BasicEventDispatcher {
private final EventDispatchChainImpl eventDispatchChain;
private final List eventDispatchers;
private final Object eventSource;
/**
* Constructs a new {@code EventRedirector}.
*
* @param eventSource the object for which to redirect the events
* ({@code RedirectedEvent} event source)
*/
public EventRedirector(final Object eventSource) {
this.eventDispatchers = new CopyOnWriteArrayList();
this.eventDispatchChain = new EventDispatchChainImpl();
this.eventSource = eventSource;
}
/**
* Called when a redirected event is received by this instance.
*
* @param eventSource the object from which the event has been redirected
* @param event the event which has been redirected
*/
protected void handleRedirectedEvent(
final Object eventSource,
final Event event) {
}
public final void addEventDispatcher(
final EventDispatcher eventDispatcher) {
eventDispatchers.add(eventDispatcher);
}
public final void removeEventDispatcher(
final EventDispatcher eventDispatcher) {
eventDispatchers.remove(eventDispatcher);
}
@Override
public final Event dispatchCapturingEvent(Event event) {
final EventType eventType = event.getEventType();
if (eventType == DirectEvent.DIRECT) {
// unwrap event, but don't redirect
event = ((DirectEvent) event).getOriginalEvent();
} else {
redirectEvent(event);
if (eventType == RedirectedEvent.REDIRECTED) {
handleRedirectedEvent(
event.getSource(),
((RedirectedEvent) event).getOriginalEvent());
}
}
return event;
}
private void redirectEvent(final Event event) {
if (!eventDispatchers.isEmpty()) {
final RedirectedEvent redirectedEvent =
(event.getEventType() == RedirectedEvent.REDIRECTED)
? (RedirectedEvent) event
: new RedirectedEvent(event, eventSource, null);
for (final EventDispatcher eventDispatcher: eventDispatchers) {
eventDispatchChain.reset();
eventDispatcher.dispatchEvent(
redirectedEvent, eventDispatchChain);
}
}
}
}