/*
 This file is part of the software framework JStatCom, 
 a library for building applications for data based analysis.

 Copyright (C) 2000-2005  Markus Kraetzig

 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, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 USA
 */

package com.jstatcom.model;
/**
 * Must be implemented by listeners that need to be notified about
 * changes in Symbol objects. A SymbolListener
 * can register itself as a listener to an event of a specific SymbolEventType
 * via Symbol.addSymbolListener.
 *
 * @author Markus Kraetzig
 */
public interface SymbolListener {

	/**
	 * Called when a Symbol object fires a SymbolEvent
	 * of a SymbolEventType that this object has registered to
	 * via Symbol.addSymbolListener.
	 * 

	 * Usage Note:

	 * All code in a valueChanged method should get all information
	 * from evt, because it might happen that the source has changed
	 * if a symbol was copied to another data table. 
	 * 
	 * @param evt the data event with all relevant information about the change 
	 */
	void valueChanged(SymbolEvent evt);
}