org.apache.catalina.util.LifecycleSupport Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.catalina.util;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleEvent;
import org.apache.catalina.LifecycleListener;
/**
* Support class to assist in firing LifecycleEvent notifications to
* registered LifecycleListeners.
*
* @author Craig R. McClanahan
* @version $Id: LifecycleSupport.java 763298 2009-04-08 16:08:42Z markt $
*/
public final class LifecycleSupport {
// ----------------------------------------------------------- Constructors
/**
* Construct a new LifecycleSupport object associated with the specified
* Lifecycle component.
*
* @param lifecycle The Lifecycle component that will be the source
* of events that we fire
*/
public LifecycleSupport(Lifecycle lifecycle) {
super();
this.lifecycle = lifecycle;
}
// ----------------------------------------------------- Instance Variables
/**
* The source component for lifecycle events that we will fire.
*/
private Lifecycle lifecycle = null;
/**
* The set of registered LifecycleListeners for event notifications.
*/
private LifecycleListener listeners[] = new LifecycleListener[0];
private final Object listenersLock = new Object(); // Lock object for changes to listeners
// --------------------------------------------------------- Public Methods
/**
* Add a lifecycle event listener to this component.
*
* @param listener The listener to add
*/
public void addLifecycleListener(LifecycleListener listener) {
synchronized (listenersLock) {
LifecycleListener results[] =
new LifecycleListener[listeners.length + 1];
for (int i = 0; i < listeners.length; i++)
results[i] = listeners[i];
results[listeners.length] = listener;
listeners = results;
}
}
/**
* Get the lifecycle listeners associated with this lifecycle. If this
* Lifecycle has no listeners registered, a zero-length array is returned.
*/
public LifecycleListener[] findLifecycleListeners() {
return listeners;
}
/**
* Notify all lifecycle event listeners that a particular event has
* occurred for this Container. The default implementation performs
* this notification synchronously using the calling thread.
*
* @param type Event type
* @param data Event data
*/
public void fireLifecycleEvent(String type, Object data) {
LifecycleEvent event = new LifecycleEvent(lifecycle, type, data);
LifecycleListener interested[] = listeners;
for (int i = 0; i < interested.length; i++)
interested[i].lifecycleEvent(event);
}
/**
* Remove a lifecycle event listener from this component.
*
* @param listener The listener to remove
*/
public void removeLifecycleListener(LifecycleListener listener) {
synchronized (listenersLock) {
int n = -1;
for (int i = 0; i < listeners.length; i++) {
if (listeners[i] == listener) {
n = i;
break;
}
}
if (n < 0)
return;
LifecycleListener results[] =
new LifecycleListener[listeners.length - 1];
int j = 0;
for (int i = 0; i < listeners.length; i++) {
if (i != n)
results[j++] = listeners[i];
}
listeners = results;
}
}
}