/**************************************************************************
* Copyright (c) 2001 by Punch Telematix. 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. Neither the name of Punch Telematix nor the names of *
* other contributors may be used to endorse or promote products *
* derived from this software without specific prior written permission.*
* *
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS 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 PUNCH TELEMATIX OR OTHER 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. *
**************************************************************************/
/*
** $Id: Observable.java,v 1.1.1.1 2004/07/12 14:07:47 cvs Exp $
*/
package java.util;
public class Observable {
private HashSet observers;
private boolean changed;
public Observable(){
observers = new HashSet(11);
}
protected void clearChanged(){
changed = false;
}
protected void setChanged(){
changed = true;
}
public void addObserver(Observer o){
if (o == null) {
throw new NullPointerException();
}
observers.add(o);
}
public int countObservers(){
return observers.size();
}
public void deleteObserver(Observer o){
observers.remove(o);
}
public void deleteObservers(){
observers.clear();
}
public boolean hasChanged(){
return changed;
}
public void notifyObservers(){
notifyObservers(null);
}
public void notifyObservers(Object arg){
if(changed) {
Iterator it = observers.iterator();
while (it.hasNext()){
((Observer)it.next()).update(this,arg);
}
changed = false;
}
}
}