// $Id: Command.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
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package org.argouml.kernel;
/**
* An executable Command
*
* @author Bob
*/
public interface Command {
/**
* Execute the command to redo an instruction.
* @return any result object created by the command
*/
public abstract Object execute();
/**
* Perform undo an an undoable command that is in an undoable state
*/
abstract void undo();
/**
* Returns true if the command can be undone.
* @return true if the command is undoable
*/
abstract boolean isUndoable();
/**
* Returns true if the command can be redone once undone
* @return true if the command is redoable
*/
abstract boolean isRedoable();
}