Tomcat example source code file (LifecycleSupport.java)

This example Tomcat source code file (LifecycleSupport.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

lifecycle, lifecycleevent, lifecycleevent, lifecyclelistener, lifecyclelistener, lifecyclesupport, lifecyclesupport, object, object

The Tomcat LifecycleSupport.java source code

/*
 * 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 510482 2007-02-22 12:34:36Z remm $
 */

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];


    // --------------------------------------------------------- Public Methods


    /**
     * Add a lifecycle event listener to this component.
     *
     * @param listener The listener to add
     */
    public void addLifecycleListener(LifecycleListener listener) {

      synchronized (listeners) {
          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 (listeners) {
            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;
        }

    }


}