com.google.web.bindery.event.shared.ResettableEventBus Maven / Gradle / Ivy
/*
* Copyright 2011 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.web.bindery.event.shared;
import com.google.web.bindery.event.shared.Event.Type;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
/**
* Wraps an EventBus to hold on to any HandlerRegistrations, so that they can
* easily all be cleared at once.
*/
public class ResettableEventBus extends EventBus {
private final EventBus wrapped;
private final Set registrations = new HashSet();
public ResettableEventBus(EventBus wrappedBus) {
this.wrapped = wrappedBus;
}
@Override
public HandlerRegistration addHandler(Type type, H handler) {
HandlerRegistration rtn = wrapped.addHandler(type, handler);
return doRegisterHandler(rtn);
}
@Override
public HandlerRegistration addHandlerToSource(Event.Type type, Object source, H handler) {
HandlerRegistration rtn = wrapped.addHandlerToSource(type, source, handler);
return doRegisterHandler(rtn);
}
@Override
public void fireEvent(Event event) {
wrapped.fireEvent(event);
}
@Override
public void fireEventFromSource(Event event, Object source) {
wrapped.fireEventFromSource(event, source);
}
/**
* Remove all handlers that have been added through this wrapper.
*/
public void removeHandlers() {
Iterator it = registrations.iterator();
while (it.hasNext()) {
HandlerRegistration r = it.next();
/*
* must remove before we call removeHandler. Might have come from nested
* ResettableEventBus
*/
it.remove();
r.removeHandler();
}
}
/**
* Visible for testing.
*/
protected int getRegistrationSize() {
return registrations.size();
}
private HandlerRegistration doRegisterHandler(final HandlerRegistration registration) {
registrations.add(registration);
return new HandlerRegistration() {
public void removeHandler() {
doUnregisterHandler(registration);
}
};
}
private void doUnregisterHandler(HandlerRegistration registration) {
if (registrations.contains(registration)) {
registration.removeHandler();
registrations.remove(registration);
}
}
}