| gvSIG desktop 1

/* gvSIG. Geographic Information System of the Valencian Government

*

* Copyright (C) 2007-2008 Infrastructures and Transports Department

* of the Valencian Government (CIT)

* 

* This program is free software; you can redistribute it and/or

* modify it under the terms of the GNU General Public License

* as published by the Free Software Foundation; either version 2

* of the License, or (at your option) any later version.

* 

* This program 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 General Public License for more details.

* 

* You should have received a copy of the GNU General Public License

* along with this program; if not, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 

* MA  02110-1301, USA.

* 

*/

/*

* AUTHORS (In addition to CIT):

* 2008 {DiSiD Technologies}  {{Task}}

*/

package org.gvsig.tools.undo;

import java.util.List;

import org.gvsig.tools.observer.WeakReferencingObservable;

/**

 * An Stack of Undo/Redo operations.

 * 

 * @author <a href="mailto:cordin@disid.com">C?sar Ordi?ana</a>

 */

public interface UndoRedoStack extends WeakReferencingObservable {

    /**

     * Undoes the following undoable elements.

     * 

     * @throws UndoException

     *             if there is an error performing de undo element

     */

    void undo() throws UndoException;

    /**

     * Undoes a number of the following undoable elements.

     * 

     * @param num

     *            the number of elements to undo

     * @throws UndoException

     *             if there is an error performing de undo element

     */

    void undo(int num) throws UndoException;

    /**

     * Re-does the following redoable elements.

     * 

     * @throws RedoException

     *             if there is an error performing de redo element

     */

    void redo() throws RedoException;

    /**

     * Re-does a number of the following redoable element.

     * 

     * @param num

     *            the number of elements to redo

     * @throws RedoException

     *             if there is an error performing de redo element

     */

    void redo(int num) throws RedoException;

    /**

     * Returns the list of UndoRedoInfo in the UNDO stack

     * 

     * @return list of UndoRedoInfo in the UNDO stack

     */

    List getUndoInfos();

    /**

     * Returns the list of UndoRedoInfo in the REDO stack

     * 

     * @return list of UndoRedoInfo in the REDO stack

     */

    List getRedoInfos();

    /**

     * If an undo can be performed on the stack.

     * 

     * @return an undo can be performed

     */

    boolean canUndo();

    /**

     * If a redo can be performed on the stack.

     * 

     * @return a redo can be performed

     */

    boolean canRedo();

}