question: synchronized void redo ( RTEditText editor ) { Stack < Operation > redoStack = getRedoStack ( editor ) ; if ( ! redoStack . empty ( ) ) { Stack < Operation > undoStack = getUndoStack ( editor ) ; Operation op = redoStack . pop ( ) ; push ( op , undoStack ) ; op . redo ( editor ) ; while ( ! redoStack . empty ( ) && op . canMerge ( redoStack . peek ( ) ) ) { op = redoStack . pop ( ) ; push ( op , undoStack ) ; op . redo ( editor ) ; } } }
target:  Re-do the last undone operation for a specific rich text editor