/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2001 Intersect Software Corporation

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/

package net.wotonomy.control;

import net.wotonomy.foundation.NSSelector;

/**
* A convenience observer for objects that do not or cannot 
* subclass EODelayedObserver.  EOObserverProxy will invoke
* an NSSelector on an object when it receives a subjectChanged
* message.
*
* @author michael@mpowers.net
* @author $Author: cgruber $
* @version $Revision: 893 $
*/
public class EOObserverProxy
    extends EODelayedObserver
{
    protected Object target;
    protected NSSelector selector;
    protected int priority;
    
 	/**
	* Constructs an EODelayedObserver that will invoke the specified selector
    * on the specified object, and will run at the specified priority.
	*/
	public EOObserverProxy ( 
        Object anObject, NSSelector aSelector, int aPriority )
    {
        target = anObject;
        selector = aSelector;
        priority = aPriority;
    }

 	/**
	* Constructs an EODelayedObserver that will invoke the specified selector
    * on the specified object, and will run at ObserverPriorityThird priority,
    * which is the default.
	*/
	public EOObserverProxy ( 
        Object anObject, NSSelector aSelector )
    {
        this( anObject, aSelector, ObserverPriorityThird );
    }

    /**
    * Returns the priority of this observer in the queue.
	* This implementation returns the priority specified
    * in the constructor.
    */
    public int priority ()
    {
        return priority;
    }

    /**
    * Notifies observer that one or more objects that
    * it is observing have changed.  The observer should
    * check all objects it is observing for changes.
    */
    public void subjectChanged ()
    {
        try
        {
            selector.invoke( target );
        }
        catch ( Exception exc )
        {
            System.out.println( "Error notifying observer: " );
            exc.printStackTrace();
        }
    }
    
}

/*
 * $Log$
 * Revision 1.1  2006/02/16 13:19:57  cgruber
 * Check in all sources in eclipse-friendly maven-enabled packages.
 *
 * Revision 1.1  2001/10/22 21:55:32  mpowers
 * This turns out to be a really useful class.
 *
 *
 */