/** | |
* Copyright 2003-2007 Jive Software. | |
* | |
* All rights reserved. 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.jivesoftware.smackx.workgroup.util; | |
import java.lang.reflect.Method; | |
import java.util.ArrayList; | |
import java.util.ListIterator; | |
/** | |
* This class is a very flexible event dispatcher which implements Runnable so that it can | |
* dispatch easily from a newly created thread. The usage of this in code is more or less: | |
* create a new instance of this class, use addListenerTriplet to add as many listeners | |
* as desired to be messaged, create a new Thread using the instance of this class created | |
* as the argument to the constructor, start the new Thread instance.<p> | |
* | |
* Also, this is intended to be used to message methods that either return void, or have | |
* a return which the developer using this class is uninterested in receiving. | |
* | |
* @author loki der quaeler | |
*/ | |
public class ListenerEventDispatcher | |
implements Runnable { | |
protected transient ArrayList<TripletContainer> triplets; | |
protected transient boolean hasFinishedDispatching; | |
protected transient boolean isRunning; | |
public ListenerEventDispatcher () { | |
super(); | |
this.triplets = new ArrayList<TripletContainer>(); | |
this.hasFinishedDispatching = false; | |
this.isRunning = false; | |
} | |
/** | |
* Add a listener triplet - the instance of the listener to be messaged, the Method on which | |
* the listener should be messaged, and the Object array of arguments to be supplied to the | |
* Method. No attempts are made to determine whether this triplet was already added.<br> | |
* | |
* Messages are dispatched in the order in which they're added via this method; so if triplet | |
* X is added after triplet Z, then triplet Z will undergo messaging prior to triplet X.<br> | |
* | |
* This method should not be called once the owning Thread instance has been started; if it | |
* is called, the triplet will not be added to the messaging queue.<br> | |
* | |
* @param listenerInstance the instance of the listener to receive the associated notification | |
* @param listenerMethod the Method instance representing the method through which notification | |
* will occur | |
* @param methodArguments the arguments supplied to the notification method | |
*/ | |
public void addListenerTriplet(Object listenerInstance, Method listenerMethod, | |
Object[] methodArguments) | |
{ | |
if (!this.isRunning) { | |
this.triplets.add(new TripletContainer(listenerInstance, listenerMethod, | |
methodArguments)); | |
} | |
} | |
/** | |
* @return whether this instance has finished dispatching its messages | |
*/ | |
public boolean hasFinished() { | |
return this.hasFinishedDispatching; | |
} | |
public void run() { | |
ListIterator<TripletContainer> li = null; | |
this.isRunning = true; | |
li = this.triplets.listIterator(); | |
while (li.hasNext()) { | |
TripletContainer tc = li.next(); | |
try { | |
tc.getListenerMethod().invoke(tc.getListenerInstance(), tc.getMethodArguments()); | |
} catch (Exception e) { | |
System.err.println("Exception dispatching an event: " + e); | |
e.printStackTrace(); | |
} | |
} | |
this.hasFinishedDispatching = true; | |
} | |
protected class TripletContainer { | |
protected Object listenerInstance; | |
protected Method listenerMethod; | |
protected Object[] methodArguments; | |
protected TripletContainer (Object inst, Method meth, Object[] args) { | |
super(); | |
this.listenerInstance = inst; | |
this.listenerMethod = meth; | |
this.methodArguments = args; | |
} | |
protected Object getListenerInstance() { | |
return this.listenerInstance; | |
} | |
protected Method getListenerMethod() { | |
return this.listenerMethod; | |
} | |
protected Object[] getMethodArguments() { | |
return this.methodArguments; | |
} | |
} | |
} |