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## javax.swing.undo
Class StateEdit

    java.lang.Object
      |
      +--javax.swing.undo.AbstractUndoableEdit
            |
            +--javax.swing.undo.StateEdit

All Implemented Interfaces:
  Serializable, UndoableEdit

public class StateEdit
extends AbstractUndoableEdit

StateEdit is a general edit for objects that change state. Objects being edited must conform to the StateEditable interface.

This edit class works by asking an object to store it's state in Hashtables before and after editing occurs. Upon undo or redo the object is told to restore it's state from these Hashtables.

A state edit is used as follows:

    	// Create the edit during the "before" state of the object
    	StateEdit newEdit = new StateEdit(myObject);
    	// Modify the object
    	myObject.someStateModifyingMethod();
    	// "end" the edit when you are done modifying the object
    	newEdit.end();

Note that when a StateEdit ends, it removes redundant state from the Hashtables - A state Hashtable is not guaranteed to contain all keys/values placed into it when the state is stored!

See Also:
  `StateEditable`

Field Summary
`protected StateEditable` | `object` The object being edited
`protected Hashtable` | `postState` The state information after the edit
`protected Hashtable` | `preState` The state information prior to the edit
`protected static String` | `RCSID`
`protected String` | `undoRedoName` The undo/redo presentation name

Fields inherited from class javax.swing.undo.AbstractUndoableEdit
`RedoName, UndoName`

Constructor Summary
`StateEdit(StateEditable anObject)` Create and return a new StateEdit.
`StateEdit(StateEditable anObject, String name)` Create and return a new StateEdit with a presentation name.

Method Summary
`void` | `end()` Gets the post-edit state of the StateEditable object and ends the edit.
`String` | `getPresentationName()` Gets the presentation name for this edit
`protected void` | `init(StateEditable anObject, String name)`
`void` | `redo()` Tells the edited object to apply the state after the edit
`protected void` | `removeRedundantState()` Remove redundant key/values in state hashtables.
`void` | `undo()` Tells the edited object to apply the state prior to the edit

Methods inherited from class javax.swing.undo.AbstractUndoableEdit
`addEdit, canRedo, canUndo, die, getRedoPresentationName, getUndoPresentationName, isSignificant, replaceEdit, toString`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

### RCSID

    protected static final String RCSID

See Also:
  Constant Field Values

### object

    protected StateEditable object

  The object being edited

### preState

    protected Hashtable preState

  The state information prior to the edit

### postState

    protected Hashtable postState

  The state information after the edit

### undoRedoName

    protected String undoRedoName

  The undo/redo presentation name

Constructor Detail

### StateEdit

    public StateEdit(StateEditable anObject)

  Create and return a new StateEdit.

Parameters:
  `anObject` - The object to watch for changing state
See Also:
  `StateEdit`

### StateEdit

    public StateEdit(StateEditable anObject,
                     String name)

  Create and return a new StateEdit with a presentation name.

Parameters:
  `anObject` - The object to watch for changing state
  `name` - The presentation name to be used for this edit
See Also:
  `StateEdit`

Method Detail

### init

    protected void init(StateEditable anObject,
                        String name)

### end

    public void end()

  Gets the post-edit state of the StateEditable object and ends the edit.

### undo

    public void undo()

  Tells the edited object to apply the state prior to the edit

  Specified by:
    `undo` in interface `UndoableEdit`
  Overrides:
    `undo` in class `AbstractUndoableEdit`
  See Also:
    `AbstractUndoableEdit.canUndo()`

### redo

    public void redo()

  Tells the edited object to apply the state after the edit

  Specified by:
    `redo` in interface `UndoableEdit`
  Overrides:
    `redo` in class `AbstractUndoableEdit`
  See Also:
    `AbstractUndoableEdit.canRedo()`

### getPresentationName

    public String getPresentationName()

  Gets the presentation name for this edit

  Specified by:
    `getPresentationName` in interface `UndoableEdit`
  Overrides:
    `getPresentationName` in class `AbstractUndoableEdit`
  Returns:
    the empty string ""
  See Also:
    `AbstractUndoableEdit.getUndoPresentationName()`, `AbstractUndoableEdit.getRedoPresentationName()`

### removeRedundantState

    protected void removeRedundantState()

  Remove redundant key/values in state hashtables.

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.