javax.swing.undo
Class AbstractUndoableEdit

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

All Implemented Interfaces:

java.io.Serializable, UndoableEdit

Direct Known Subclasses:

AbstractDocument.ElementEdit, CompoundEdit

public class AbstractUndoableEdit

extends java.lang.Object

implements UndoableEdit, java.io.Serializable

An abstract implementation of UndoableEdit, implementing simple responses to all boolean methods in that interface.

Constructor Summary

protected

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

Method Summary

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.
java.lang.String	getPresentationName() This default implementation returns "".
boolean	isSignificant() This default implementation returns true.
void	redo() Throws CannotRedoException if canRedo returns false.
boolean	replaceEdit(UndoableEdit anEdit) This default implementation returns false.
java.lang.String	toString() Returns a string that displays and identifies this object's properties.
void	undo() Throws CannotUndoException if canUndo returns false.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractUndoableEdit

protected AbstractUndoableEdit()

Creates an AbstractUndoableEdit which defaults and alive to true.

Method Detail

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.

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 java.lang.String getPresentationName()

This default implementation returns "". Subclasses should override to return an appropriate description of the operation this edit represents.

Specified by:

getPresentationName in interface UndoableEdit

Returns:

the empty string ""

toString

public java.lang.String toString()

Returns a string that displays and identifies this object's properties.

Returns:

a String representation of this object