void linkBefore ( E e , Node < E > succ ) { // assert succ != null; final Node < E > pred = succ . prev ; final Node < E > newNode = new Node <> ( pred , e , succ ) ; succ . prev = newNode ; if ( pred == null ) first = newNode ; else pred . next = newNode ; size ++ ; modCount ++ ; }
Inserts element e before non - null Node succ .