/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.custom;


import org.eclipse.swt.internal.SWTEventListener;

/**
 * The StyledText widget implements this listener to receive
 * notifications when changes to the model occur.
 * It is not intended to be implemented by clients or by 
 * implementors of StyledTextContent. 
 * Clients should listen to the ModifyEvent or ExtendedModifyEvent 
 * that is sent by the StyledText widget to receive text change 
 * notifications.
 * Implementors of StyledTextContent should call the textChanging
 * and textChanged methods when text changes occur as described 
 * below. If the entire text is replaced the textSet method 
 * should be called instead.
 */
public interface TextChangeListener extends SWTEventListener {

/**
 * This method is called when the content is about to be changed.
 * Callers also need to call the textChanged method after the 
 * content change has been applied. The widget only updates the 
 * screen properly when it receives both events. 
 * 
 * @param event the text changing event. All event fields need
 * 	to be set by the sender.
 * @see TextChangingEvent
 */
public void textChanging(TextChangingEvent event);
/**
 * This method is called when the content has changed.
 * Callers need to have called the textChanging method prior to 
 * applying the content change and calling this method. The widget 
 * only updates the screen properly when it receives both events.
 * 
 * @param event the text changed event
 */
public void textChanged(TextChangedEvent event);
/**
 * This method is called instead of the textChanging/textChanged 
 * combination when the entire old content has been replaced 
 * (e.g., by a call to StyledTextContent.setText()).
 * 
 * @param event the text changed event
 */
public void textSet(TextChangedEvent event);
}


