code: public PropertyList<Property> getProperties(final String paramValue) {
          PropertyList<Property> properties = index.get(paramValue);
          if (properties == null) {
              properties = EMPTY_LIST;
          }
          return properties;
      }
docs: Returns a list of properties containing a parameter with the
  specified value.
  @param paramValue the value of the parameter contained in the
  returned properties
  @return a property list