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/*
* Copyright 2000-2013 Vaadin Ltd.
*
* 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.vaadin.tests.minitutorials.broadcastingmessages;
import java.util.ArrayList;
import java.util.List;
public class Broadcaster {
private static List<BroadcastListener> listeners = new ArrayList<BroadcastListener>();
public synchronized static void register(BroadcastListener listener) {
listeners.add(listener);
}
public synchronized static void unregister(BroadcastListener listener) {
listeners.remove(listener);
}
private synchronized static List<BroadcastListener> getListeners() {
List<BroadcastListener> listenerCopy = new ArrayList<BroadcastListener>();
listenerCopy.addAll(listeners);
return listenerCopy;
}
public static void broadcast(final String message) {
// Make a copy of the listener list while synchronized, can't be
// synchronized while firing the event or we would have to fire each
// event in a separate thread.
final List<BroadcastListener> listenerCopy = getListeners();
// We spawn another thread to avoid potential deadlocks with
// multiple UIs locked simultaneously
Thread eventThread = new Thread() {
@Override
public void run() {
for (BroadcastListener listener : listenerCopy) {
listener.receiveBroadcast(message);
}
}
};
eventThread.start();
}
public interface BroadcastListener {
public void receiveBroadcast(String message);
}
}
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