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:: com :: sun :: star :: document ::

interface XUndoManager
Base Interfaces
XUndoManager
┣ ::com::sun::star::util::XLockable
┗ ::com::sun::star::container::XChild

::com::sun::star::util::XLockable
Description
allows locking the undo manager.
::com::sun::star::container::XChild
Description
allows accessing the component, usually a document, which the undo manager works for.

::com::sun::star::container::XChild::setParent is not supported, and will throw an ::com::sun::star::lang::NoSupportException.

Description
provides access to the undo/redo stacks of a document

Undo

Changes to a document usually result in recording of information how to undo those changes, if desired. A so-called undo action records the information how to undo a single change. Undo actions are maintained in a stack, so that the changes they represent can be undo in the reverse order they have originally been applied.

Redo

Additionally, the Undo manager manages a Redo stack: Actions which are undone are moved from the Undo to the Redo stack, so it is possible to re-apply the changes to the document.

Undo contexts

For collecting multiple changes in a single undo action, so-called Undo contexts are provided. When an Undo context is entered, all subsequently added Undo actions are not pushed onto the undo stack directly, but considered a sub action of the Undo context. Once the Undo context is left, a single undo action is pushed onto the undo stack, which comprises all those single Undo actions.
Undo contexts can be arbitrarily nested.

Hidden Undo actions

Hidden Undo actions are those which in no observable way contribute to the undo stack. That is, any method retrieving information about the stack will behave as if the undo action does not exist. Nonetheless, calling undo respectively redo will include those actions.
Hidden Undo actions can be created by calling enterHiddenUndoContext, following by leaveUndoContext.

Locking

An Undo manager can be locked and unlocked, using the ::XLockable::lock and ::XLockable::unlock methods. When it is locked, then every attempt to add an undo action, or to enter or leave an Undo context, will be silently ignored.


Methods' Summary
enterUndoContext enters a new undo context.  
enterHiddenUndoContext enters a new undo context, creating a hidden undo action.  
leaveUndoContext leaves the undo context previously opened via enterUndoContext respectively enterHiddenUndoContext.  
addUndoAction adds the given undo action to the undo stack.  
undo reverts the most recent action on the document.  
redo replays the action on the document which has most recently been undone  
isUndoPossible determines whether undo can reasonably be expected to succeed.  
isRedoPossible determines whether redo can reasonably be expected to succeed.  
getCurrentUndoActionTitle returns the title of the top-most action on the undo stack  
getCurrentRedoActionTitle returns the title of the top-most action on the Redo stack  
getAllUndoActionTitles returns the titles of all actions currently on the undo stack, from top to bottom  
getAllRedoActionTitles returns the titles of all actions currently on the Redo stack, from top to bottom  
clear clears the undo and the redo stack.  
clearRedo clears the redo stack.  
reset resets the Undo manager  
addUndoManagerListener adds a listener to be notified of changes in the Undo/Redo stacks.  
removeUndoManagerListener removes a previously added listener  
Methods' Details
enterUndoContext
void
enterUndoContext( [in] string  i_title );

Description
enters a new undo context.

A new undo action will be added to the undo stack, with the title given as i_title. As long as the context is not left, every undo action added to the stack will be treated as sub action. This means it will not be directly accessible at the Undo manager, not appear in any user interface, and cannot be separately undone or re-done.

Each call to enterUndoContext must be paired by a call to leaveUndoContext, otherwise, the document's undo stack is left in an inconsistent state.

Undo contexts can be nested, i.e. it is legitimate to call enterUndoContext and enterHiddenUndoContext multiple times without calling leaveUndoContext inbetween.

See also
leaveUndoContext
enterHiddenUndoContext
void
enterHiddenUndoContext()
raises( EmptyUndoStackException );

Description
enters a new undo context, creating a hidden undo action.

A hidden undo action does not, in any visible way, contribute to the undo stack. This means that

  • Calling undo when the top-element is a hidden undo action will transparently undo this action, and also undo the new top element of the stack.
  • Calling redo when the top-element is a hidden action will transparently redo this action, and also redo the new top element of the stack.
  • In any user interface presenting the current Undo or Redo actions to the user, a hidden action will not be listed.

A new undo action will be added to the undo stack. As long as the context is not left, every undo action added to the stack will be treated as sub action. This means it will not be directly accessible at the undo manager, not appear in any user interface, and cannot be separately undone or re-done.

Each call to enterHiddenUndoContext must be paired by a call to leaveUndoContext, otherwise, the document's undo stack is left in an inconsistent state.

Undo contexts can be nested, i.e. it is legitimate to call enterUndoContext and enterHiddenUndoContext multiple times without calling leaveUndoContext inbetween.

Throws
EmptyUndoStackException if the undo stack is currently empty, in which case it is impossible to push a hidden undo action onto it.
See also
enterUndoContext, leaveUndoContext
leaveUndoContext
void
leaveUndoContext()
raises( ::com::sun::star::util::InvalidStateException );

Description
leaves the undo context previously opened via enterUndoContext respectively enterHiddenUndoContext.

If no undo action has been added since the context has been opened, the context is not only left, but silently removed, and does not contribute to the undo stack at all. In this case, possible listeners will be notified via XUndoManagerListener::cancelledContext.

Otherwise, the undo context will be closed, and added to the Undo stack; the redo stack will be cleared, and listeners will be notified via XUndoManagerListener::leftContext resp. XUndoManagerListener::leftHiddenContext

Throws
::com::sun::star::util::InvalidStateException if no undo context is currently open.
See also
enterUndoContext, enterHiddenUndoContext
addUndoAction
void
addUndoAction( [in] XUndoAction  i_action )
raises( ::com::sun::star::lang::IllegalArgumentException );

Description
adds the given undo action to the undo stack.

The redo stack is cleared when a new action is pushed onto the undo stack.

The Undo manager takes ownership of any actions pushed onto the undo stack. This means that if the action is finally removed from the Undo manager's control (e.g. by calling clear resp. clearRedo), it will be disposed, as long as it supports the XComponent interface.

If the Undo manager is locked at the moment the method is called, the call will be ignored, and the undo action will immediately be disposed, if applicable.

Throws
::com::sun::star::lang::IllegalArgumentException if the given undo action is NULL.
undo
void
undo()
raises( EmptyUndoStackException,
UndoContextNotClosedException,
UndoFailedException );

Description
reverts the most recent action on the document.

Effectively, invoking this method will

  • invoke XUndoAction::undo on the top-most action of the undo stack
  • move this undo action from the undo stack to the redo stack

Throws
EmptyUndoStackException if the undo stack is currently empty
Throws
UndoContextNotClosedException if there currently is an open undo context
Throws
UndoFailedException if the invocation of XUndoAction::undo raised this exception. In this case, the undo stack of the undo manager will have been cleared.
See also
redo, enterUndoContext
redo
void
redo()
raises( EmptyUndoStackException,
UndoContextNotClosedException,
UndoFailedException );

Description
replays the action on the document which has most recently been undone

Effectively, invoking this method will

  • invoke XUndoAction::redo on the top-most action of the redo stack
  • move this action from the redo stack to the undo stack

Throws
EmptyUndoStackException when the Redo stack is currently empty
Throws
UndoContextNotClosedException if there currently is an open undo context
Throws
UndoFailedException if the invocation of XUndoAction::redo raised this exception. In this case, the redo stack of the undo manager will have been cleared.
See also
undo
isUndoPossible
boolean
isUndoPossible();

Description
determines whether undo can reasonably be expected to succeed.
Returns
false if and only if the undo stack is currently empty, or there is an open and not-yet-closed undo context.
isRedoPossible
boolean
isRedoPossible();

Description
determines whether redo can reasonably be expected to succeed.
Returns
false if and only if the redo stack is currently empty, or there is an open and not-yet-closed undo context.
getCurrentUndoActionTitle
string
getCurrentUndoActionTitle()
raises( EmptyUndoStackException );

Description
returns the title of the top-most action on the undo stack
Throws
EmptyUndoStackException when the undo stack is currently empty
See also
XUndoAction::Title
getCurrentRedoActionTitle
string
getCurrentRedoActionTitle()
raises( EmptyUndoStackException );

Description
returns the title of the top-most action on the Redo stack
Throws
EmptyUndoStackException when the Redo stack is currently empty
See also
XUndoAction::Title
getAllUndoActionTitles
sequence< string >
getAllUndoActionTitles();

Description
returns the titles of all actions currently on the undo stack, from top to bottom
See also
XUndoAction::Title
getAllRedoActionTitles
sequence< string >
getAllRedoActionTitles();

Description
returns the titles of all actions currently on the Redo stack, from top to bottom
See also
XUndoAction::Title
clear
void
clear()
raises( UndoContextNotClosedException );

Description
clears the undo and the redo stack.

All actions will be removed from both the Undo and the Redo stack. Actions which implement the ::com::sun::star::lang::XComponent interface will be disposed.

Throws
UndoContextNotClosedException if the method is invoked while an undo context is still open
clearRedo
void
clearRedo()
raises( UndoContextNotClosedException );

Description
clears the redo stack.

All actions will be removed from the Redo stack. Actions which implement the ::com::sun::star::lang::XComponent interface will be disposed.

Throws
UndoContextNotClosedException if the method is invoked while an undo context is still open
reset
void
reset();

Description
resets the Undo manager

In particular, this method will

  • remove all locks from the undo manager
  • close all open undo contexts
  • clear the undo stack
  • clear the redo stack

Note that possible listeners will not get notifications for the single parts of the reset, i.e. there will be no single XUndoManagerListener::allActionsCleared, XUndoManagerListener::leftContext, etc., notifications. Instead, listeners will be notified of the reset by calling their XUndoManagerListener::resetAll method.

addUndoManagerListener
void
addUndoManagerListener( [in] XUndoManagerListener  i_listener );

Description
adds a listener to be notified of changes in the Undo/Redo stacks.
removeUndoManagerListener
void
removeUndoManagerListener( [in] XUndoManagerListener  i_listener );

Description
removes a previously added listener
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