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:

Clients may implement this interface or use the standard implementation TextViewerUndoManager.

See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    beginCompoundChange()
    Signals the undo manager that all subsequent changes until endCompoundChange is called are to be undone in one piece.
    void
    connect(ITextViewer viewer)
    Connects this undo manager to the given text viewer.
    void
    disconnect()
    Disconnects this undo manager from its text viewer.
    void
    endCompoundChange()
    Signals the undo manager that the sequence of changes which started with beginCompoundChange 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.

  • Method Details

    • connect

      void connect(ITextViewer viewer)
      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 until endCompoundChange is called are to be undone in one piece.

    • endCompoundChange

      void endCompoundChange()
      Signals the undo manager that the sequence of changes which started with beginCompoundChange 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.