code: public List<P> findAllPresentationModelsByType(String type) {
          if (StringUtil.isBlank(type) || !modelsPerType.containsKey(type)) return Collections.emptyList();
          return Collections.unmodifiableList(modelsPerType.get(type));
      }
docs: Finds all presentation models that share the same type.<br/>
  The returned {@code List} is never null (though it may be empty), and is immutable.
  
  @param type the type to search for
  @return a {@code List} of all presentation models with the specified type.