/**
* Adds the value to the collection given by map.get(key). A new collection is created using the
* supplied CollectionFactory.
*/
public static <K, V, C extends Collection<V>> void putIntoValueCollection(
Map<K, C> map, K key, V value, CollectionFactory<V> cf) {
C c = map.get(key);
if (c == null) {
c = ErasureUtils.<C>uncheckedCast(cf.newCollection());
map.put(key, c);
}
c.add(value);
}
