code: public StructuredQueryDefinition propertiesConstraint(String constraintName, StructuredQueryDefinition query) {
      checkQuery(query);
      return new PropertiesConstraintQuery(constraintName, query);
    }
docs: Associates a query with the properties of documents (as opposed to
  the content of documents) with the specified constraint.
  @param constraintName    the constraint definition
  @param query    the query definition
  @return    the StructuredQueryDefinition for the properties constraint query