public synchronized void undoOrRedo() throws CannotRedoException, CannotUndoException {  }
public synchronized void undoOrRedo() throws CannotRedoException, CannotUndoException { if (indexOfNextAdd == edits.size()) undo(); else redo(); }
	public synchronized void undoOrRedo() throws CannotRedoException, CannotUndoException {		// TODO	} // undoOrRedo()