Malformed requests

The SparqlHelperConfig.setErrorsHandlingType(char errorsHandlingType) specifies how the SPARQLParser should behave for malformed requests:

• The ErrorsHandlingType.EXCEPTION specifies that a MalformedQueryException will be thrown for malformed queries
• The ErrorsHandlingType.EMPTY_QUERY specifies that no exception will be thrown for malformed queries, but a query with no matches will be generated

Behavior with the EXCEPTION value

If SparqlHelperConfig.getErrorsHandlingType() is set to ErrorsHandlingType.EXCEPTION, a MalformedQueryException will be thrown for malformed queries.

For example for the following request:

   SELECT ?zone
   WHER {
     ?zone rdf:type sitac:TaskZone .
     ?zone sitac:isTasked "true" .
   }

To parse this request, we can do:

   SPARQLParser parser = new SPARQLParser("sitac");
   SparqlRequest request = parser.parseQuery(<the request String>);

The following code will throw a MalformedQueryException.

Behavior with the EMPTY_QUERY value

If SparqlHelperConfig.getErrorsHandlingType() is set to ErrorsHandlingType.EMPTY_QUERY, malformed queries will generate a query withj no matches, and the resulting query will be set as not well-formed.

For example for the following request:

   SELECT ?zone
   WHER {
     ?zone rdf:type sitac:TaskZone .
     ?zone sitac:isTasked "true" .
   }

To parse this request, we can do:

   SparqlHelperConfig.getInstance().setErrorsHandlingType(ErrorsHandlingType.EMPTY_QUERY);      
   SPARQLParser parser = new SPARQLParser("sitac");
   SparqlRequest request = parser.parseQuery(<the request String>);
   boolean isValid = request.isWellformed(); // will return false

If you perform:

   String parsedQuery = request.toString();

You will have the following content:

   SELECT *
   WHERE {
      ?o rdf:type owl:Thing .
   }
   LIMIT 0