@Override
        public Set<java.util.Map.Entry<K, IntegerFieldValue>> entrySet() {
            Map<K, IntegerFieldValue> ret = new HashMap<>();
            for (Map.Entry e : map.entrySet()) {
                ret.put(wrapKey(e.getKey()), wrapValue(e.getValue()));
            }
            return ret.entrySet();
        }
Weighted set MapFieldValue, backed by map of native Java types.
Note: The key type of this is FieldValue, not K.
@author vegardh
document/src/main/java/com/yahoo/document/datatypes/WeightedSet.java