/*
* Copyright (C) 2014 The Android Open Source Project
*
* 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 libcore.net.event;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* A singleton used to dispatch network events to registered listeners.
*/
public class NetworkEventDispatcher {
private static final NetworkEventDispatcher instance = new NetworkEventDispatcher();
private final List<NetworkEventListener> listeners =
new CopyOnWriteArrayList<NetworkEventListener>();
/**
* Returns the shared {@link NetworkEventDispatcher} instance.
*/
public static NetworkEventDispatcher getInstance() {
return instance;
}
/** Visible for testing. Use {@link #getInstance()} instead. */
protected NetworkEventDispatcher() {
}
/**
* Registers a listener to be notified when network events occur.
* It can be deregistered using {@link #removeListener(NetworkEventListener)}
*/
public void addListener(NetworkEventListener toAdd) {
if (toAdd == null) {
throw new NullPointerException("toAdd == null");
}
listeners.add(toAdd);
}
/**
* De-registers a listener previously added with {@link #addListener(NetworkEventListener)}. If
* the listener was not previously registered this is a no-op.
*/
public void removeListener(NetworkEventListener toRemove) {
for (NetworkEventListener listener : listeners) {
if (listener == toRemove) {
listeners.remove(listener);
return;
}
}
}
/**
* Notifies registered listeners of a network configuration change.
*/
public void onNetworkConfigurationChanged() {
for (NetworkEventListener listener : listeners) {
try {
listener.onNetworkConfigurationChanged();
} catch (RuntimeException e) {
System.logI("Exception thrown during network event propagation", e);
}
}
}
}