使用上一个迭代器的逆序列表

Question

I want to start at the end of the list and iterate it using ListIterators previous method

public void add(E obj) {    
    ListIterator <E> iter = theList.listIterator();
    while (iter.hasNext()) {
        if (obj.compareTo(iter.next()) < 0) {
            iter.previous();
            iter.add(obj);
            return;
        }
    }
    iter.add(obj);
}

Every time I run my test class it iterators from the beginning.

Answer 1

to get iterator in reverse order use method list.listIterator(int index) this method will return iterator from specified position, you should put size of list means last element index. after that you can use hasPrevious() and previous() method. this will work,

 // declare arraylist
 ArrayList<...> a = new ArrayList<...>();

 // Add elements to list.

 // Generate an iterator. Start just after the last element.
 ListIterator li = a.listIterator(a.size());

 // Iterate in reverse.
  while(li.hasPrevious()) {
      System.out.println(li.previous());
  }

Answer 2

ListIterator, like all Iterators, always start at the beginning. The previous method allows for less constrained movement, but it still starts at the beginning. You overall intent is unclear, so it's possible you're coming at this the wrong way, but the most straightforward way for you would be to reorder the list first and then do your iteration.

UPDATE Nevermind, Rajj has it.