/**
   * Query SPARQL endpoint with a SELECT query
   *
   * @param qExec QueryExecution encapsulating the query
   * @return model retrieved by querying the endpoint
   */
  private Model getSelectModel(QueryExecution qExec) {
    Model model = ModelFactory.createDefaultModel();
    Graph graph = model.getGraph();
    ResultSet results = qExec.execSelect();

    while (results.hasNext()) {
      QuerySolution sol = results.next();
      String subject;
      String predicate;
      RDFNode object;

      try {
        subject = sol.getResource("s").toString();
        predicate = sol.getResource("p").toString();
        object = sol.get("o");
      } catch (NoSuchElementException e) {
        logger.error("SELECT query does not return a (?s ?p ?o) Triple");
        continue;
      }

      Node objNode;
      if (object.isLiteral()) {
        Literal obj = object.asLiteral();
        objNode = NodeFactory.createLiteral(obj.getString(), obj.getDatatype());
      } else {
        objNode = NodeFactory.createLiteral(object.toString());
      }

      graph.add(
          new Triple(NodeFactory.createURI(subject), NodeFactory.createURI(predicate), objNode));
    }

    return model;
  }
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  void runTestSelect(Query query, QueryExecution qe) throws Exception {
    // Do the query!
    ResultSetRewindable resultsActual = ResultSetFactory.makeRewindable(qe.execSelect());

    qe.close();

    if (results == null) return;

    // Assumes resultSetCompare can cope with full isomorphism possibilities.
    ResultSetRewindable resultsExpected;
    if (results.isResultSet())
      resultsExpected = ResultSetFactory.makeRewindable(results.getResultSet());
    else if (results.isModel())
      resultsExpected = ResultSetFactory.makeRewindable(results.getModel());
    else {
      fail("Wrong result type for SELECT query");
      resultsExpected = null; // Keep the compiler happy
    }

    if (query.isReduced()) {
      // Reduced - best we can do is DISTINCT
      resultsExpected = unique(resultsExpected);
      resultsActual = unique(resultsActual);
    }

    // Hack for CSV : tests involving bNodes need manually checking.
    if (testItem.getResultFile().endsWith(".csv")) {
      resultsActual = convertToStrings(resultsActual);
      resultsActual.reset();

      int nActual = ResultSetFormatter.consume(resultsActual);
      int nExpected = ResultSetFormatter.consume(resultsExpected);
      resultsActual.reset();
      resultsExpected.reset();
      assertEquals("CSV: Different number of rows", nExpected, nActual);
      boolean b = resultSetEquivalent(query, resultsExpected, resultsActual);
      if (!b) System.out.println("Manual check of CSV results required: " + testItem.getName());
      return;
    }

    boolean b = resultSetEquivalent(query, resultsExpected, resultsActual);

    if (!b) {
      resultsExpected.reset();
      resultsActual.reset();
      boolean b2 = resultSetEquivalent(query, resultsExpected, resultsActual);
      printFailedResultSetTest(query, qe, resultsExpected, resultsActual);
    }
    assertTrue("Results do not match: " + testItem.getName(), b);

    return;
  }
Esempio n. 3
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  /**
   * Perform the {@link QueryExecution} once.
   *
   * @param action
   * @param queryExecution
   * @param query
   * @param queryStringLog Informational string created from the initial query.
   * @return
   */
  protected SPARQLResult executeQuery(
      HttpAction action, QueryExecution queryExecution, Query query, String queryStringLog) {
    setAnyTimeouts(queryExecution, action);

    if (query.isSelectType()) {
      ResultSet rs = queryExecution.execSelect();

      // Force some query execution now.
      // If the timeout-first-row goes off, the output stream has not
      // been started so the HTTP error code is sent.

      rs.hasNext();

      // If we wanted perfect query time cancellation, we could consume
      // the result now to see if the timeout-end-of-query goes off.
      // rs = ResultSetFactory.copyResults(rs) ;

      // action.log.info(format("[%d] exec/select", action.id)) ;
      return new SPARQLResult(rs);
    }

    if (query.isConstructType()) {
      Dataset dataset = queryExecution.execConstructDataset();
      // action.log.info(format("[%d] exec/construct", action.id));
      return new SPARQLResult(dataset);
    }

    if (query.isDescribeType()) {
      Model model = queryExecution.execDescribe();
      // action.log.info(format("[%d] exec/describe", action.id)) ;
      return new SPARQLResult(model);
    }

    if (query.isAskType()) {
      boolean b = queryExecution.execAsk();
      // action.log.info(format("[%d] exec/ask", action.id)) ;
      return new SPARQLResult(b);
    }

    ServletOps.errorBadRequest("Unknown query type - " + queryStringLog);
    return null;
  }
  /**
   * Returns the string value of the first of the properties in the uriDescriptionList for the given
   * resource (as an URI). In case the resource does not have any of the properties mentioned, its
   * URI is returned. The value is obtained by querying the endpoint and the endpoint is queried
   * repeatedly until it gives a response (value or the lack of it)
   *
   * <p>It is highly recommended that the list contains properties like labels or titles, with test
   * values.
   *
   * @param uri - the URI for which a label is required
   * @return a String value, either a label for the parameter or its value if no label is obtained
   *     from the endpoint
   */
  private String getLabelForUri(String uri) {
    String result;

    if (uriLabelCache.containsKey(uri)) {
      return uriLabelCache.get(uri);
    }

    for (String prop : uriDescriptionList) {
      String innerQuery = "SELECT ?r WHERE {<" + uri + "> <" + prop + "> ?r } LIMIT 1";

      try {
        Query query = QueryFactory.create(innerQuery);
        QueryExecution qExec = QueryExecutionFactory.sparqlService(rdfEndpoint, query);
        boolean keepTrying = true;
        while (keepTrying) {
          keepTrying = false;
          try {
            ResultSet results = qExec.execSelect();

            if (results.hasNext()) {
              QuerySolution sol = results.nextSolution();
              result = EEASettings.parseForJson(sol.getLiteral("r").getLexicalForm());
              if (!result.isEmpty()) {
                uriLabelCache.put(uri, result);
                return result;
              }
            }
          } catch (Exception e) {
            keepTrying = true;
            logger.warn("Could not get label for uri {}. Retrying.", uri);
          } finally {
            qExec.close();
          }
        }
      } catch (QueryParseException qpe) {
        logger.error("Exception for query {}. The label cannot be obtained", innerQuery);
      }
    }
    return uri;
  }
  /**
   * Get a set of unique queryObjName returned from a select query
   *
   * <p>Used to retrieve sets of modified objects used in sync
   *
   * @param rdfQuery query to execute
   * @param queryObjName name of the object returned
   * @return set of values for queryObjectName in the rdfQuery result
   */
  HashSet<String> executeSyncQuery(String rdfQuery, String queryObjName) {
    HashSet<String> rdfUrls = new HashSet<String>();

    Query query;
    try {
      query = QueryFactory.create(rdfQuery);
    } catch (QueryParseException qpe) {
      logger.warn(
          "Could not parse [{}]. Please provide a relevant query. {}",
          rdfQuery,
          qpe.getLocalizedMessage());
      return null;
    }

    QueryExecution qExec = QueryExecutionFactory.sparqlService(rdfEndpoint, query);
    try {
      ResultSet results = qExec.execSelect();

      while (results.hasNext()) {
        QuerySolution sol = results.nextSolution();
        try {
          String value = sol.getResource(queryObjName).toString();
          rdfUrls.add(value);
        } catch (NoSuchElementException e) {
          logger.error("Encountered a NoSuchElementException: " + e.getLocalizedMessage());
          return null;
        }
      }
    } catch (Exception e) {
      logger.error(
          "Encountered a [{}] while querying the endpoint for sync", e.getLocalizedMessage());
      return null;
    } finally {
      qExec.close();
    }

    return rdfUrls;
  }