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Cayenne Object Persistence Framework including all dependencies.
There is a newer version: 1.2.4
/* ====================================================================
 *
 * The ObjectStyle Group Software License, version 1.1
 * ObjectStyle Group - http://objectstyle.org/
 * 
 * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
 * of the software. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 
 * 3. The end-user documentation included with the redistribution, if any,
 *    must include the following acknowlegement:
 *    "This product includes software developed by independent contributors
 *    and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 * 
 * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
 *    or promote products derived from this software without prior written
 *    permission. For written permission, email
 *    "andrus at objectstyle dot org".
 * 
 * 5. Products derived from this software may not be called "ObjectStyle"
 *    or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
 *    names without prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 * 
 * This software consists of voluntary contributions made by many
 * individuals and hosted on ObjectStyle Group web site.  For more
 * information on the ObjectStyle Group, please see
 * .
 */
package org.objectstyle.cayenne.dataview;

import java.util.ArrayList;
import java.util.EventListener;

public class EventDispatcher {
  protected transient ArrayList listeners = new ArrayList(1);

  public void dispatch(DispatchableEvent e) {
    EventListener[] listenersCopy = null;
    synchronized(this) {
      if (hasListeners())
        listenersCopy = (EventListener[])listeners.toArray(new EventListener[listeners.size()]);
    }

    if (listenersCopy != null) {
      int count = listenersCopy.length;
      for (int index = 0; index < count; ++index) {
        e.dispatch(listenersCopy[index]);
      }
    }
  }

  public synchronized boolean hasListeners() {
    return !listeners.isEmpty();
  }

  public synchronized int getListenerCount() {
    return listeners.size();
  }

  public synchronized int find(EventListener listener) {
    return listeners.indexOf(listener);
  }

  public synchronized void add(EventListener listener) {
    if (find(listener) < 0)
      listeners.add(listener);
  }

  public synchronized void remove(EventListener listener) {
    listeners.remove(listener);
  }

  public synchronized void clear() {
    listeners.clear();
  }

  public static EventDispatcher add(EventDispatcher dispatcher, EventListener listener) {
    if (dispatcher == null)
      dispatcher = new EventDispatcher();
    dispatcher.add(listener);
    return dispatcher;
  }

  public final static EventDispatcher remove(EventDispatcher dispatcher, EventListener listener) {
    if (dispatcher != null) {
      dispatcher.remove(listener);
      if (!dispatcher.hasListeners())
        dispatcher = null;
    }
    return dispatcher;
  }
}