/*
* Copyright 2010 the original author or authors.
*
* 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 org.gradle.internal.event;
import org.gradle.api.Action;
import org.gradle.internal.dispatch.Dispatch;
import org.gradle.internal.dispatch.MethodInvocation;
import org.gradle.internal.dispatch.ProxyDispatchAdapter;
import java.util.Collection;
/**
* <p>Manages a set of listeners of type T. Provides an implementation of T which can be used to broadcast to all
* registered listeners.</p>
*
* <p>Ordering is maintained for events, so that events are delivered to listeners in the order they are generated.
* Events are delivered to listeners in the order that listeners are added to this broadcaster.</p>
*
* <p>Implementations are not thread-safe.</p>
*
* @param <T> The listener type.
*/
public class ListenerBroadcast<T> implements Dispatch<MethodInvocation> {
private ProxyDispatchAdapter<T> source;
private BroadcastDispatch<T> broadcast;
private final Class<T> type;
public ListenerBroadcast(Class<T> type) {
this.type = type;
broadcast = BroadcastDispatch.empty(type);
}
/**
* Returns the broadcaster. Any method call on this object is broadcast to all listeners.
*
* @return The broadcaster.
*/
public T getSource() {
if (source == null) {
source = new ProxyDispatchAdapter<T>(this, type);
}
return source.getSource();
}
/**
* Returns the type of listener to which this class broadcasts.
*
* @return The type of the broadcaster.
*/
public Class<T> getType() {
return type;
}
/**
* Returns {@code true} if no listeners are registered with this object.
*
* @return {@code true} if no listeners are registered with this object, {@code false} otherwise
*/
public boolean isEmpty() {
return broadcast.isEmpty();
}
/**
* Adds a listener.
*
* @param listener The listener.
*/
public void add(T listener) {
broadcast = broadcast.add(listener);
}
/**
* Adds the given listeners.
*
* @param listeners The listeners
*/
public void addAll(Collection<? extends T> listeners) {
broadcast = broadcast.addAll(listeners);
}
/**
* Adds a {@link Dispatch} to receive events from this broadcast.
*/
public void add(Dispatch<MethodInvocation> dispatch) {
broadcast = broadcast.add(dispatch);
}
/**
* Adds an action to be executed when the given method is called.
*/
public void add(String methodName, Action<?> action) {
broadcast = broadcast.add(methodName, action);
}
/**
* Removes the given listener.
*
* @param listener The listener.
*/
public void remove(Object listener) {
broadcast = broadcast.remove(listener);
}
/**
* Removes the given listeners.
*
* @param listeners The listeners
*/
public void removeAll(Collection<?> listeners) {
broadcast = broadcast.removeAll(listeners);
}
/**
* Removes all listeners.
*/
public void removeAll() {
broadcast = BroadcastDispatch.empty(type);
}
/**
* Broadcasts the given event to all listeners.
*
* @param event The event
*/
public void dispatch(MethodInvocation event) {
broadcast.dispatch(event);
}
}