Class mxUndoManager

java.lang.Object
com.mxgraph.util.mxEventSource
com.mxgraph.util.mxUndoManager

public class mxUndoManager extends mxEventSource
Implements an undo history. This class fires the following events: mxEvent.CLEAR fires after clear was executed. The event has no properties. mxEvent.UNDO fires afer a significant edit was undone in undo. The edit property contains the mxUndoableEdit that was undone. mxEvent.REDO fires afer a significant edit was redone in redo. The edit property contains the mxUndoableEdit that was redone. mxEvent.ADD fires after an undoable edit was added to the history. The edit property contains the mxUndoableEdit that was added.
  • Field Details

    • size

      protected int size
      Maximum command history size. 0 means unlimited history. Default is 100.
    • history

      protected List<mxUndoableEdit> history
      List that contains the steps of the command history.
    • indexOfNextAdd

      protected int indexOfNextAdd
      Index of the element to be added next.
  • Constructor Details

    • mxUndoManager

      public mxUndoManager()
      Constructs a new undo manager with a default history size.
    • mxUndoManager

      public mxUndoManager(int size)
      Constructs a new undo manager for the specified size.
  • Method Details

    • isEmpty

      public boolean isEmpty()
    • clear

      public void clear()
      Clears the command history.
    • canUndo

      public boolean canUndo()
      Returns true if an undo is possible.
    • undo

      public void undo()
      Undoes the last change.
    • canRedo

      public boolean canRedo()
      Returns true if a redo is possible.
    • redo

      public void redo()
      Redoes the last change.
    • undoableEditHappened

      public void undoableEditHappened(mxUndoableEdit undoableEdit)
      Method to be called to add new undoable edits to the history.
    • trim

      protected void trim()
      Removes all pending steps after indexOfNextAdd from the history, invoking die on each edit. This is called from undoableEditHappened.