Class: Undo/UndoManager

Undo class is the Java Object for undo/redo. UndoManager keeps a Vector of Undo objects for VTT to perform undo/redo operation. The undo object includes:

• Action
  • ADD (0)
  • CHANGE (1)
  • DELETE (2)
• Cur (current Markup)
• Prev (previous Markup)

The UML class diagram is shown below:

Please refer to undo/redo operation for design details.