code: public final Set<Attribute> getAttributes(final Class<?> _class)
      {
          final Set<Attribute> ret = new HashSet<>();
          for (final Attribute attr : getAttributes().values()) {
              if (attr.getAttributeType().getClassRepr().isAssignableFrom(_class)) {
                  ret.add(attr);
              }
          }
          return ret;
      }
docs: The instance method returns all attributes which are from the same
  attribute type as the described with the parameter <i>_class</i>.
  
  @param _class searched attribute type
  @return all attributes assigned from parameter <i>_class</i>