/*
* Copyright (c) 2005-2016 Vincent Vandenschrick. All rights reserved.
*
* This file is part of the Jspresso framework.
*
* Jspresso 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 3 of the License, or
* (at your option) any later version.
*
* Jspresso 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 Jspresso. If not, see <http://www.gnu.org/licenses/>.
*/
package org.jspresso.framework.util.event;
/**
* This public interface has to be implemented by classes wishing to keep track
* of of value modifications. This is typically used when binding two connectors
* together (in a MVC relationship for instance) where the 2 connectors will
* listen for each other value.
*
* @author Vincent Vandenschrick
*/
public interface IValueChangeListener {
/**
* This method is triggered whenever a source detects that its value changed.
* Ideally this method will only fire when {@code oldValue} differs from
* {@code newValue}.
*
* @param evt
* The event representing the change. This event will have : <li>
* {@code source} set to the source which initiated the event.
* <li>{@code oldValue} set to the old value of the source. <li>
* {@code newValue} set to the new value of the source.
*/
void valueChange(ValueChangeEvent evt);
}