// $Id: UndoManager.java 40 2010-04-03 19:25:46Z marcusvnac $
// Copyright (c) 2007 The Regents of the University of California. All
// Rights Reserved. Permission to use, copy, modify, and distribute this
// software and its documentation without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph appear in all copies. This software program and
// documentation are copyrighted by The Regents of the University of
// California. The software program and documentation are supplied "AS
// IS", without any accompanying services from The Regents. The Regents
// does not warrant that the operation of the program will be
// uninterrupted or error-free. The end-user understands that the program
// was developed for research purposes and is advised not to rely
// exclusively on the program for any reason. IN NO EVENT SHALL THE
// UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
// SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,
// ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
// THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
// PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
// CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,
// UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
package org.argouml.kernel;
import java.beans.PropertyChangeListener;
/**
* Stores Commands that have been executed and allows them to be undone
* and redone. Commands represent single operations on the ArgoUML model.
* A single user interaction may generate several Commands. Undo/redo
* works an a user interaction and so can undo/redo several commands in one
* call.
*
* @author Bob Tarling
*/
public interface UndoManager {
/**
* Adds a new command to the undo stack.
* @param command the command.
*/
public abstract void addCommand(Command command);
/**
* Execute a command and add it to the undo stack.
*
* @param command the command.
* @return any resulting object the command creates
*/
public abstract Object execute(Command command);
/**
* Set the maximum number of interactions the stack can hold.
* @param max the maximum chain count
*/
public abstract void setUndoMax(int max);
/**
* Undo the top user interaction on the undo stack and move
* it to the redo stack.
*/
public abstract void undo();
/**
* Redo the top user interaction on the redo stack and move
* it to the undo stack.
*/
public abstract void redo();
/**
* Instructs the UndoManager that a new user interaction is about to take
* place. All commands received until the next call to startInteraction will
* form a single undoable unit.
*
* @param label the label for this interaction to build the undo/redo label
*/
public abstract void startInteraction(String label);
/**
* Add a new PropertyChangeListener for undo/redo events. Allow a listener
* to detect when the undo or redo stack changes availability. No guarantees
* are made about which thread the event will be delivered on, so any
* specific thread requirements (e.g. Swing/AWT thread requirements) must be
* dealt with by the
* {@link PropertyChangeListener#propertyChange(java.beans.PropertyChangeEvent)}
* method.
*
* @param listener a PropertyChangeListener
*/
public abstract void addPropertyChangeListener(
PropertyChangeListener listener);
/**
* Remove the given listener.
* @param listener a PropertyChangeListener
*/
public abstract void removePropertyChangeListener(
PropertyChangeListener listener);
}