Method multiset

storm-server/src/main/java/org/apache/storm/Testing.java:592–603

Count how many times each element appears in the Collection. @param c a collection of values @return a map of the unique values in c to the count of those values.

(Collection<T> c)

     * @return a map of the unique values in c to the count of those values.
     */
    public static <T> Map<T, Integer> multiset(Collection<T> c) {
        Map<T, Integer> ret = new HashMap<T, Integer>();
        for (T t : c) {
            Integer i = ret.get(t);
            if (i == null) {
                i = new Integer(0);
            }
            i += 1;
            ret.put(t, i);
        }
        return ret;
    }

    private static void printRec(Object o, String prefix) {
        if (o instanceof Collection) {