Package org.eclipse.jface.text
Interface IUndoManager
- All Known Implementing Classes:
DefaultUndoManager
,TextViewerUndoManager
public interface IUndoManager
An undo manager is connected to at most one
ITextViewer
.
It monitors the text viewer and keeps a history of the changes applied to the viewer. The undo manager groups those changes into user interactions which on an undo request are rolled back in one atomic change.
In order to provide backward compatibility for clients of IUndoManager
, extension
interfaces are used as a means of evolution. The following extension interfaces exist:
IUndoManagerExtension
since version 3.1 introducing access to the undo context.
Clients may implement this interface or use the standard implementation
TextViewerUndoManager
.
- See Also:
-
Method Summary
Modifier and TypeMethodDescriptionvoid
Signals the undo manager that all subsequent changes untilendCompoundChange
is called are to be undone in one piece.void
connect
(ITextViewer viewer) Connects this undo manager to the given text viewer.void
Disconnects this undo manager from its text viewer.void
Signals the undo manager that the sequence of changes which started withbeginCompoundChange
has been finished.void
redo()
Repeats the most recently rolled back text change.boolean
redoable()
Returns whether at least one text change can be repeated.void
reset()
Resets the history of the undo manager.void
setMaximalUndoLevel
(int undoLevel) The given parameter determines the maximal length of the history remembered by the undo manager.void
undo()
Rolls back the most recently executed text change.boolean
undoable()
Returns whether at least one text change can be rolled back.
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Method Details
-
connect
Connects this undo manager to the given text viewer.- Parameters:
viewer
- the viewer the undo manager is connected to
-
disconnect
void disconnect()Disconnects this undo manager from its text viewer. If this undo manager hasn't been connected before this operation has no effect. -
beginCompoundChange
void beginCompoundChange()Signals the undo manager that all subsequent changes untilendCompoundChange
is called are to be undone in one piece. -
endCompoundChange
void endCompoundChange()Signals the undo manager that the sequence of changes which started withbeginCompoundChange
has been finished. All subsequent changes are considered to be individually undo-able. -
reset
void reset()Resets the history of the undo manager. After that call, there aren't any undo-able or redo-able text changes. -
setMaximalUndoLevel
void setMaximalUndoLevel(int undoLevel) The given parameter determines the maximal length of the history remembered by the undo manager.- Parameters:
undoLevel
- the length of this undo manager's history
-
undoable
boolean undoable()Returns whether at least one text change can be rolled back.- Returns:
true
if at least one text change can be rolled back
-
redoable
boolean redoable()Returns whether at least one text change can be repeated. A text change can be repeated only if it was executed and rolled back.- Returns:
true
if at least on text change can be repeated
-
undo
void undo()Rolls back the most recently executed text change. -
redo
void redo()Repeats the most recently rolled back text change.
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