Ptidej-v5.2-master/POM Tests/data/ArgoUML_0.28/src/org/argouml/model/ModelCommand.java
// $Id: ModelCommand.java 13530 2007-09-11 06:07:38Z tfmorris $
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package org.argouml.model;

/**
 * A command to record the state of an object before an undoable change.<p>
 * The model implementation should create a ModelCommand for any
 * undoable operation performed. Any mutator method should normally be
 * undoable except loading a model from file.
 * 
 * @author Bob Tarling
 */
public abstract class ModelCommand {

    /**
     * Execute this command.
     * @return any result generated by this command
     */
    public abstract Object execute();

    /**
     * Determine whether the command can be undone.
     * 
     * @return true if the command can be undone
     */
    public abstract boolean isUndoable();

    /**
     * Determine whether the command can be redone once undone.
     * 
     * @return true if the command can be redone
     */
    public abstract boolean isRedoable();

    /**
     * Undo this command.
     */
    public abstract void undo();
}
