code: public <T> void put(Class<?> type, PrefabValueFactory<T> factory) {
          if (type != null) {
              cache.put(type.getName(), factory);
          }
      }
docs: Adds the given factory to the cache and associates it with the given
  type.
  
  @param <T> The type of the factory.
  @param type The type to associate with the factory.
  @param factory The factory to associate with the type.