org.pepsoft.util.undo

Class UndoManager

java.lang.Object

org.pepsoft.util.undo.UndoManager

public class UndoManager
extends Object

A data buffer oriented (rather than edit list or operations oriented) manager of undo and redo data. Uses a copy on write mechanism to maintain a list of historical versions of a set of data buffers, copying them automatically when needed after a save point has been executed, and notifying clients when buffers need to be updated because an undo or redo has been performed.

Constructor Summary

Constructors

Constructor and Description
UndoManager()
UndoManager(Action undoAction, Action redoAction)
UndoManager(Action undoAction, Action redoAction, int maxFrames)
UndoManager(int maxFrames)

Method Summary

Modifier and Type	Method and Description
<T> void	addBuffer(BufferKey<T> key, T buffer)
<T> void	addBuffer(BufferKey<T> key, T buffer, UndoListener listener)
void	addListener(UndoListener listener)
void	armSavePoint() Arm a save point.
void	clear() Throw away all undo and redo information.
void	clearRedo() Throw away all redo information
<T> T	getBuffer(BufferKey<T> key)
<T> T	getBufferForEditing(BufferKey<T> key)
long	getDataSize()
int	getMaxFrames()
Snapshot	getSnapshot() Get a read-only snapshot of the current state of the buffers.
Class<?>[]	getStopAtClasses()
boolean	isDirty() Indicates whether the current history frame is dirty (meaning that buffers have been checked out for editing from it).
boolean	redo() Rolls forward all buffers to the next save point, if there is one available, and no edits have been performed since the last undo.
void	registerActions(Action undoAction, Action redoAction)
void	removeBuffer(BufferKey<?> key)
void	removeListener(UndoListener listener)
void	savePoint() Save the current state of all buffers as an undo point.
void	setStopAtClasses(Class<?>... stopAt)
boolean	undo() Rolls back all buffers to the previous save point, if there is one still available.
void	unregisterActions()

Methods inherited from class java.lang.Object

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

Constructor Detail

UndoManager

public UndoManager()

UndoManager

public UndoManager(int maxFrames)

UndoManager

public UndoManager(Action undoAction,
                   Action redoAction)

UndoManager

public UndoManager(Action undoAction,
                   Action redoAction,
                   int maxFrames)

Method Detail

registerActions

public void registerActions(Action undoAction,
                            Action redoAction)

unregisterActions

public void unregisterActions()

getMaxFrames

public int getMaxFrames()

armSavePoint

public void armSavePoint()

Arm a save point. It will be executed the next time a buffer is requested for editing. Arming a save point instead of executing it immediately allows a redo to be performed instead.

Will do nothing if a save point is already armed, or if the current frame is the last one and it is not dirty.

savePoint

public void savePoint()

Save the current state of all buffers as an undo point.

getSnapshot

public Snapshot getSnapshot()

Get a read-only snapshot of the current state of the buffers. If you want the state to be a static snapshot that will not reflect later changes, you should execute a save point after getting the snapshot. The snapshot will remain valid until the corresponding undo history frame disappears, after which it will throw an exception if you try to use it.

Returns:

A snapshot of the current undo history frame.

isDirty

public boolean isDirty()

Indicates whether the current history frame is dirty (meaning that buffers have been checked out for editing from it).

Returns:

true if the current history frame is dirty.

undo

public boolean undo()

Rolls back all buffers to the previous save point, if there is one still available.

Returns:

true if the undo was succesful.

redo

public boolean redo()

Rolls forward all buffers to the next save point, if there is one available, and no edits have been performed since the last undo.

Returns:

true if the redo was succesful.

clear

public void clear()

Throw away all undo and redo information.

clearRedo

public void clearRedo()

Throw away all redo information

addBuffer

public <T> void addBuffer(BufferKey<T> key,
                          T buffer)

addBuffer

public <T> void addBuffer(BufferKey<T> key,
                          T buffer,
                          UndoListener listener)

removeBuffer

public void removeBuffer(BufferKey<?> key)

getBuffer

public <T> T getBuffer(BufferKey<T> key)

getBufferForEditing

public <T> T getBufferForEditing(BufferKey<T> key)

addListener

public void addListener(UndoListener listener)

removeListener

public void removeListener(UndoListener listener)

getStopAtClasses

public Class<?>[] getStopAtClasses()

setStopAtClasses

public void setStopAtClasses(Class<?>... stopAt)

getDataSize

public long getDataSize()