com.compdfkit.core.undo

Interface CPDFUndoManager

public interface CPDFUndoManager

A generic manager for undoing/redoing.

Method Summary

Modifier and Type	Method and Description
void	addLogListener(CPDFUndoLogListener logListener) Adds an CPDFUndoLogListener for debug
void	addOnUndoHistoryChangeListener(OnUndoHistoryChangeListener onUndoHistoryChangeListener) Adds an OnUndoHistoryChangeListener for being notified of changes to the undo manager's edit history (i.e.
boolean	canRedo() Returns whether there are edits that can be redone or not.
boolean	canUndo() Returns whether there are edits that can be undone or not.
void	clearHistory() Clears the history of all currently recorded edits.
void	enable(boolean enable) Whether to enable the undoing/redoing.
boolean	isEnable() Returns the enabled status for undoing/redoing.
void	redo() Redoes the next edit or throws an exception if a redo operation is not possible.
void	removeOnUndoHistoryChangeListener(OnUndoHistoryChangeListener onUndoHistoryChangeListener) Removes a previously added OnUndoHistoryChangeListener.
void	undo() Undoes the last edit or throws an exception if an undo operation is not possible.It's recommended that you check whether an undo operation is available using canUndo() before calling this method.

Method Detail

canUndo

boolean canUndo()

Returns whether there are edits that can be undone or not. If this returns false a call to undo() will throw an exception.

Returns:

True if an undo operation is possible, false otherwise.

canRedo

boolean canRedo()

Returns whether there are edits that can be redone or not. If this returns false a call to redo() will throw an exception.

Returns:

True if a redo operation is possible, false otherwise.

undo

void undo()
   throws CPDFUndoFailedException

Undoes the last edit or throws an exception if an undo operation is not possible.It's recommended that you check whether an undo operation is available using canUndo() before calling this method. Undoing may be unavailable if there are no edits on the undo stack or if the latest edit on the undo stack cannot be undone. When undoing an edit, the edit is moved to the internal redo stack.

Throws:

CPDFUndoFailedException - Thrown if an undo operation was unsuccessful, if the undo stack was empty, or if the last edit is not undoable.

redo

void redo()
   throws CPDFRedoFailedException

Redoes the next edit or throws an exception if a redo operation is not possible. It's recommended that you check whether a redo operation is available using canRedo() ()} before calling this method. Redoing may be unavailable if there are no edits on the redo stack or if the latest edit on the redo stack cannot be redone. When redoing an edit, the edit is moved to the internal undo stack.

Throws:

CPDFRedoFailedException - Thrown if redo operation was unsuccessful, if the redo stack was empty, or if the last edit is not redoable.

clearHistory

void clearHistory()

Clears the history of all currently recorded edits. After calling this method, this CPDFUndoManager will have no edits that can be undone or redone.

addOnUndoHistoryChangeListener

void addOnUndoHistoryChangeListener(OnUndoHistoryChangeListener onUndoHistoryChangeListener)

Adds an OnUndoHistoryChangeListener for being notified of changes to the undo manager's edit history (i.e. its undo and redo stacks). If a listener has already been added previously, this method will be a no-op. See Also removeOnUndoHistoryChangeListener(OnUndoHistoryChangeListener).

Parameters:

onUndoHistoryChangeListener - That should be notified

removeOnUndoHistoryChangeListener

void removeOnUndoHistoryChangeListener(OnUndoHistoryChangeListener onUndoHistoryChangeListener)

Removes a previously added OnUndoHistoryChangeListener. Upon calling this method, listener will no longer be notified of any changes. If listener has not been added previously, this method will be a no-op. See Also addOnUndoHistoryChangeListener(OnUndoHistoryChangeListener).

Parameters:

onUndoHistoryChangeListener - That should be removed.

enable

void enable(boolean enable)

Whether to enable the undoing/redoing.

Parameters:

enable - True if the undoing/redoing is enabled, false otherwise.

isEnable

boolean isEnable()

Returns the enabled status for undoing/redoing. Default is disable.

Returns:

True if the undoing/redoing is enabled, false otherwise.

addLogListener

void addLogListener(CPDFUndoLogListener logListener)

Adds an CPDFUndoLogListener for debug

Parameters:

logListener - That should be notified