redo the last command : pop the a command from the redostack execute the redo method push the command to the undostack concode_field_sep Stack<Command> redoStack concode_elem_sep Stack<Command> undoStack concode_field_sep void undo concode_elem_sep void clearHistory concode_elem_sep void execute
void function ( ) { if ( ! redoStack . isEmpty ( ) ) { Command loc0 = redoStack . pop ( ) ; loc0 . redo ( ) ; undoStack . push ( loc0 ) ; } }