Module java.desktop
Package javax.swing.undo

# Class AbstractUndoableEdit

java.lang.Object
javax.swing.undo.AbstractUndoableEdit

All Implemented Interfaces:
  `Serializable`, `UndoableEdit`

Direct Known Subclasses:
  `AbstractDocument.ElementEdit`, `CompoundEdit`, `DefaultStyledDocument.AttributeUndoableEdit`, `StateEdit`

public class AbstractUndoableEdit extends Object implements UndoableEdit, Serializable
An abstract implementation of `UndoableEdit`, implementing simple responses to all boolean methods in that interface.

## Field Summary

Fields
Modifier and Type
Field
Description
`protected static final String`
`RedoName`
String returned by `getRedoPresentationName`; as of Java 2 platform v1.3.1 this field is no longer used.
`protected static final String`
`UndoName`
String returned by `getUndoPresentationName`; as of Java 2 platform v1.3.1 this field is no longer used.

## Constructor Summary

Constructors
Constructor
Description
`AbstractUndoableEdit()`
Creates an `AbstractUndoableEdit` which defaults `hasBeenDone` and `alive` to `true`.

## Method Summary

Modifier and Type
Method
Description
`boolean`
`addEdit(UndoableEdit anEdit)`
This default implementation returns false.
`boolean`
`canRedo()`
Returns `true` if this edit is `alive` and `hasBeenDone` is `false`.
`boolean`
`canUndo()`
Returns true if this edit is `alive` and `hasBeenDone` is `true`.
`void`
`die()`
Sets `alive` to false.
`String`
`getPresentationName()`
This default implementation returns "".
`String`
`getRedoPresentationName()`
Retrieves the value from the defaults table with key `AbstractUndoableEdit.redoText` and returns that value followed by a space, followed by `getPresentationName`.
`String`
`getUndoPresentationName()`
Retrieves the value from the defaults table with key `AbstractUndoableEdit.undoText` and returns that value followed by a space, followed by `getPresentationName`.
`boolean`
`isSignificant()`
This default implementation returns true.
`void`
`redo()`
Throws `CannotRedoException` if `canRedo` returns false.
`boolean`
`replaceEdit(UndoableEdit anEdit)`
This default implementation returns false.
`String`
`toString()`
Returns a string that displays and identifies this object's properties.
`void`
`undo()`
Throws `CannotUndoException` if `canUndo` returns `false`.

### Methods declared in class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

## Field Details

### UndoName

protected static final String UndoName
String returned by `getUndoPresentationName`; as of Java 2 platform v1.3.1 this field is no longer used. This value is now localized and comes from the defaults table with key `AbstractUndoableEdit.undoText`.

See Also:
  - `UIDefaults`
  - Constant Field Values

### RedoName

protected static final String RedoName
String returned by `getRedoPresentationName`; as of Java 2 platform v1.3.1 this field is no longer used. This value is now localized and comes from the defaults table with key `AbstractUndoableEdit.redoText`.

See Also:
  - `UIDefaults`
  - Constant Field Values

## Constructor Details

### AbstractUndoableEdit

public AbstractUndoableEdit()
Creates an `AbstractUndoableEdit` which defaults `hasBeenDone` and `alive` to `true`.

## Method Details

### die

public void die()
Sets `alive` to false. Note that this is a one way operation; dead edits cannot be resurrected. Sending `undo` or `redo` to a dead edit results in an exception being thrown.

Typically an edit is killed when it is consolidated by another edit's `addEdit` or `replaceEdit` method, or when it is dequeued from an `UndoManager`.

Specified by:
  `die` in interface `UndoableEdit`
See Also:
  - `CompoundEdit.die()`

### undo

public void undo() throws CannotUndoException
Throws `CannotUndoException` if `canUndo` returns `false`. Sets `hasBeenDone` to `false`. Subclasses should override to undo the operation represented by this edit. Override should begin with a call to super.

Specified by:
  `undo` in interface `UndoableEdit`
Throws:
  `CannotUndoException` - if `canUndo` returns `false`
See Also:
  - `canUndo()`

### canUndo

public boolean canUndo()
Returns true if this edit is `alive` and `hasBeenDone` is `true`.

Specified by:
  `canUndo` in interface `UndoableEdit`
Returns:
  true if this edit is `alive` and `hasBeenDone` is `true`
See Also:
  - `die()`
  - `undo()`
  - `redo()`

### redo

public void redo() throws CannotRedoException
Throws `CannotRedoException` if `canRedo` returns false. Sets `hasBeenDone` to `true`. Subclasses should override to redo the operation represented by this edit. Override should begin with a call to super.

Specified by:
  `redo` in interface `UndoableEdit`
Throws:
  `CannotRedoException` - if `canRedo` returns `false`
See Also:
  - `canRedo()`

### canRedo

public boolean canRedo()
Returns `true` if this edit is `alive` and `hasBeenDone` is `false`.

Specified by:
  `canRedo` in interface `UndoableEdit`
Returns:
  `true` if this edit is `alive` and `hasBeenDone` is `false`
See Also:
  - `die()`
  - `undo()`
  - `redo()`

### addEdit

public boolean addEdit(UndoableEdit anEdit)
This default implementation returns false.

Specified by:
  `addEdit` in interface `UndoableEdit`
Parameters:
  `anEdit` - the edit to be added
Returns:
  false
See Also:
  - `UndoableEdit.addEdit(javax.swing.undo.UndoableEdit)`

### replaceEdit

public boolean replaceEdit(UndoableEdit anEdit)
This default implementation returns false.

Specified by:
  `replaceEdit` in interface `UndoableEdit`
Parameters:
  `anEdit` - the edit to replace
Returns:
  false
See Also:
  - `UndoableEdit.replaceEdit(javax.swing.undo.UndoableEdit)`

### isSignificant

public boolean isSignificant()
This default implementation returns true.

Specified by:
  `isSignificant` in interface `UndoableEdit`
Returns:
  true
See Also:
  - `UndoableEdit.isSignificant()`

### getPresentationName

public String getPresentationName()
This default implementation returns "". Used by `getUndoPresentationName` and `getRedoPresentationName` to construct the strings they return. Subclasses should override to return an appropriate description of the operation this edit represents.

Specified by:
  `getPresentationName` in interface `UndoableEdit`
Returns:
  the empty string ""
See Also:
  - `getUndoPresentationName()`
  - `getRedoPresentationName()`

### getUndoPresentationName

public String getUndoPresentationName()
Retrieves the value from the defaults table with key `AbstractUndoableEdit.undoText` and returns that value followed by a space, followed by `getPresentationName`. If `getPresentationName` returns "", then the defaults value is returned alone.

Specified by:
  `getUndoPresentationName` in interface `UndoableEdit`
Returns:
  the value from the defaults table with key `AbstractUndoableEdit.undoText`, followed by a space, followed by `getPresentationName` unless `getPresentationName` is "" in which case, the defaults value is returned alone.
See Also:
  - `getPresentationName()`

### getRedoPresentationName

public String getRedoPresentationName()
Retrieves the value from the defaults table with key `AbstractUndoableEdit.redoText` and returns that value followed by a space, followed by `getPresentationName`. If `getPresentationName` returns "", then the defaults value is returned alone.

Specified by:
  `getRedoPresentationName` in interface `UndoableEdit`
Returns:
  the value from the defaults table with key `AbstractUndoableEdit.redoText`, followed by a space, followed by `getPresentationName` unless `getPresentationName` is "" in which case, the defaults value is returned alone.
See Also:
  - `getPresentationName()`

### toString

public String toString()
Returns a string that displays and identifies this object's properties.

Overrides:
  `toString` in class `Object`
Returns:
  a String representation of this object