Method to sort any map with numeric value from greatest to least.

Code:

    private static Map<?, ?> sort(final Map<?, ? extends Number> map) {
        String s= null;
        Comparator c = new Comparator<Object>() {
            @Override
            public int compare(Object a, Object b) {
                if (map.get(a).doubleValue() >= map.get(b).doubleValue()) {
                    return -1;
                } else {
                    return 1;
                }
            }
        };
        TreeMap<Object, Object> tm = new TreeMap<Object , Object>(c);
        tm.putAll((Map<Object, ? extends Number>) map);
        return (Map<Object, Object>) tm;
    }

Very interested in a better way to do this if anyone has one.

Usage

Code:

Map<String, Integer> map = new HashMap<String, Integer>();
//put some map sets
map = sort(map); //cast needed, you got this.

Test outputs

Code:

Five: 5 Three: 3 One: 1 Two: 2 Four: 4 unsorted
Five: 5 Four: 4 Three: 3 Two: 2 One: 1 sorted
1.1 double: 1.1 2.2 double: 2.2 4.4 double: 4.4 5.5 double: 5.5 3.3 double: 3.3 unsorted
5.5 double: 5.5 4.4 double: 4.4 3.3 double: 3.3 2.2 double: 2.2 1.1 double: 1.1 sorted
5.5 float: 5.5 2.2 float: 2.2 1.1 float: 1.1 3.3 float: 3.3 4.4 float: 4.4 unsorted
5.5 float: 5.5 4.4 float: 4.4 3.3 float: 3.3 2.2 float: 2.2 1.1 float: 1.1 sorted

for least to greatest, change

Code:

                if (map.get(a).doubleValue() >= map.get(b).doubleValue()) {
                    return -1;
                } else {
                    return 1;
                }

to

Code:

                if (map.get(a).doubleValue() >= map.get(b).doubleValue()) {
                    return 1;
                } else {
                    return -1;
                }

 

Probably worth noting that if you're using a list you can use Collections.sort().

 

Bukkit bundles Guava, so you can just do the whole thing in two lines:

Code:java

valueComparator =Ordering.natural().onResultOf(Functions.forMap(map));
map =ImmutableSortedMap.copyOf(myOriginalMap, valueComparator);
 

Sorting the Map live is a bit more advanced, but also easily possible as shown in this answer on stackoverflow (where I also happen to copy the above examples from).