Undo and redo functions with the Java Implementation Editor

With the Java implementation of the editor's Undo, redo function, very convenient, the following is a realization of this function of the class,

import java.awt.event.ActionEvent;


import javax.swing.AbstractAction;


import javax.swing.Action;


import Javax.swing.JEditorPane;


import Javax.swing.KeyStroke;


import javax.swing.event.UndoableEditEvent;


import Javax.swing.event.UndoableEditListener;


import javax.swing.text.JTextComponent;


import javax.swing.undo.CannotRedoException;


import javax.swing.undo.CannotUndoException;


import Javax.swing.undo.UndoManager;


/**


* Undowrapper is responsible for adding undo and redo support to text components.


* @author Antonio Vieiro (antonio@antonioshome.net), $Author: $


* @version $Revision: $


*/


public class Undowrapper


implements Undoableeditlistener


{


private UndoManager UndoManager;


private UndoAction undoaction;


private redoaction redoaction;


private JEditorPane textcomponent;





　 /**


* Creates a new instance of Undowrapper


　 */


public Undowrapper (JEditorPane acomponent)


　 {


textcomponent = acomponent;


UndoManager = new UndoManager ();


undoaction = new UndoAction ();


redoaction = new RedoAction ();


textcomponent.getdocument (). Addundoableeditlistener (this);


Textcomponent.getinputmap (). put (keystroke) undoaction.getvalue (


Action.accelerator_key), "undo");


Textcomponent.getinputmap (). put (keystroke) redoaction.getvalue (


action.accelerator_key), "Redo");


Textcomponent.getactionmap (). Put ("undo", UndoAction);


Textcomponent.getactionmap (). Put ("Redo", redoaction);


　 }





public void undoableedithappened (Undoableeditevent e)


　 {


Undomanager.addedit (E.getedit ());


undoaction.updateundostate ();


redoaction.updateredostate ();


　 }





　 /**


* UndoAction is the Action responsible for handling the undo operation.


　 */


class UndoAction


extends AbstractAction


　 {


public undoaction ()


　　 {


Super ("Cannot undo"); todo:i18n


setenabled (FALSE);


Putvalue (Action.accelerator_key, Keystroke.getkeystroke ("Ctrl Z"));


　　 }





public void actionperformed (ActionEvent e)


　　 {


Try


　　　 {


Undomanager.undo ();


　　　 }


catch (cannotundoexception cue)


　　　 {


//todo:use logging?


Cue.printstacktrace (System.err);


　　　 }


updateundostate ();


redoaction.updateredostate ();


　　 }





void Updateundostate ()


　　 {


if (Undomanager.canundo ())


　　　 {


setenabled (TRUE);


Putvalue (Action.name, "Undo"); TODO i18n


　　　 }


Else


　　　 {


setenabled (FALSE);


Putvalue (Action.name, "cannot undo"); TODO i18n


　　　 }


　　 }


　 }





　 /**


* RedoAction is the Action responsible for handling the redo operation.


　 */


class RedoAction


extends AbstractAction


　 {


public redoaction ()


　　 {


super ("Cannot redo"); TODO i18n


setenabled (FALSE);


Putvalue (Action.accelerator_key, Keystroke.getkeystroke ("Ctrl Y"));


　　 }


public void actionperformed (ActionEvent e)


　　 {


Try


　　　 {


Undomanager.redo ();


　　　 }


catch (cannotredoexception CRE)


　　　 {


//todo:use logging?


Cre.printstacktrace (System.err);


　　　 }


updateredostate ();


undoaction.updateundostate ();


　　 }





void Updateredostate ()


　　 {


if (Undomanager.canredo ())


　　　 {


setenabled (TRUE);


Putvalue (Action.name, "Redo"); TODO i18n


　　　 }


Else


　　　 {


setenabled (FALSE);


Putvalue (Action.name, "cannot redo"); TODO i18n


　　　 }


　　 }


　 }





undoaction getundoaction ()


　 {


return undoaction;


　 }





redoaction getredoaction ()


　 {


return redoaction;


　 }


}

When you use it, you just need to pass the jeditorpane you created as an object into the Undowrapper. Use the following method as new Undowrapper (Editorpane);

Ok so your editor has the undo Redo function, and is not limited by the number of times.