Descending Sorting of an ArrayList of Object

Question

I need to sort this ArrayObject :

public ArrayList<WPPost> posts;

on descending :

posts.get(i).getRating()

I have tried with HashMaps, LinkedHashMaps, I haven't found anything. What's the best solution ?

Answer 1

I think that one of the best solutions is the use of Collections.sort

    Collections.sort(posts, new Comparator<WPPost>() {
        @Override
        public int compare(WPPost o1, WPPost o2) {
            return o2.getRating() - o1.getRating();
        }
    });

In some implemetations Collectios sort use merge sort algorithm, that will give you a O(log n) complexity.