Java: SortedMap, TreeMap, Comparable? How to use?

Question

I have a list of objects I need to sort according to properties of one of their fields. I\'ve heard that SortedMap and Comparators are the best way to do this.

Answer 1

My answer assumes you are using the TreeMap implementation of SortedMap.

1.) If using TreeMap, you have a choice. You can either implement Comparable directly on your class or pass a separate Comparator to the constructor.

2.) Example:

Comparator cmp = new MyComparator();
Map map = new TreeMap(myComparator);

3.) Yes that's correct. Internally TreeMap uses a red-black tree to store elements in order as they are inserted; the time cost of performing an insert (or retrieval) is O(log N).