code: protected void insertAfterEntry(T e, T insertPos) {
          T oldNext = insertPos.getNext();
          e.setNext(oldNext);
          e.setPrev(insertPos);
          insertPos.setNext(e);
          if (oldNext != null) {
              oldNext.setPrev(e);
          } else {
              last = e;
          }
          size++;
      }
docs: Inserts a new entry <i>after</i> a given one.
  
  @param e
  the entry to add.
  @param insertPos
  the entry before which to add the new one.