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/*
* Copyright 2013 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;
/**
* A utility class to help deal with {@link HandlerRegistration handler registrations}.
*/
public class HandlerRegistrations {
private static class HandlerRegistrationCollection implements HandlerRegistration {
private HandlerRegistration[] handlers;
public HandlerRegistrationCollection(HandlerRegistration... handlers) {
this.handlers = handlers;
}
@Override
public void removeHandler() {
if (handlers == null) {
return;
}
for (HandlerRegistration hr : handlers) {
hr.removeHandler();
}
// make sure we remove the handlers to avoid potential leaks
// if someone fails to null out their reference to us
handlers = null;
}
}
/**
* Create and return a {@link HandlerRegistration} that will call
* {@link HandlerRegistration#removeHandler()} on all supplied handlers if
* {@link HandlerRegistration#removeHandler()} is called on the returned object.
*
*
* A simple example:
* HandlerRegistration hr1 = ...
* HandlerRegistration hr2 = ...
* return HandlerRegistrations.compose(hr1, hr2);
*
*
* @param handlers the {@link HandlerRegistration handler registrations} that should be composed
* into a single {@link HandlerRegistration}
* @return the composed {@link HandlerRegistration}
*/
public static HandlerRegistration compose(HandlerRegistration... handlers) {
return new HandlerRegistrationCollection(handlers);
}
/**
* For know this is a utility class, make it not instantiable.
*/
private HandlerRegistrations() {
}
}