sparqlstore.py 文件源码

def contexts(self, triple=None):
        """
        Iterates over results to "SELECT ?NAME { GRAPH ?NAME { ?s ?p ?o } }"
        or "SELECT ?NAME { GRAPH ?NAME {} }" if triple is `None`.

        Returns instances of this store with the SPARQL wrapper
        object updated via addNamedGraph(?NAME).

        This causes a named-graph-uri key / value  pair to be sent over
        the protocol.

        Please note that some SPARQL endpoints are not able to find empty named
        graphs.
        """
        self.resetQuery()

        if triple:
            nts = self.node_to_sparql
            s, p, o = triple
            params = (nts(s if s else Variable('s')),
                      nts(p if p else Variable('p')),
                      nts(o if o else Variable('o')))
            self.setQuery('SELECT ?name WHERE { GRAPH ?name { %s %s %s }}' % params)
        else:
            self.setQuery('SELECT ?name WHERE { GRAPH ?name {} }')

        doc = ElementTree.parse(SPARQLWrapper.query(self).response)

        return (
            rt.get(Variable("name"))
            for rt, vars in _traverse_sparql_result_dom(
                doc, as_dictionary=True, node_from_result=self.node_from_result)
        )

    # Namespace persistence interface implementation