Class HTTPGraphQuery

All Implemented Interfaces:
GraphQuery, Operation, Query

public class HTTPGraphQuery extends AbstractHTTPQuery implements GraphQuery
GraphQuery implementation specific to the HTTP protocol. Methods in this class may throw the specific RepositoryException subclass UnautorizedException, the semantics of which is defined by the HTTP protocol.
Arjohn Kampman, Herko ter Horst, Andreas Schwarte
See Also:
  • Constructor Details

    • HTTPGraphQuery

      public HTTPGraphQuery(org.eclipse.rdf4j.repository.http.HTTPRepositoryConnection conn, QueryLanguage ql, String queryString, String baseURI)
  • Method Details

    • evaluate

      public GraphQueryResult evaluate() throws QueryEvaluationException
      Specified by:
      evaluate in interface GraphQuery
    • evaluate

      public void evaluate(RDFHandler handler) throws QueryEvaluationException, RDFHandlerException
      Specified by:
      evaluate in interface GraphQuery
    • explain

      public Explanation explain(Explanation.Level level)
      Description copied from interface: Query

      Explain how the query will be (or has been) executed/evaluated by returning an explanation of the query plan.

      This method is useful for understanding why a particular query is slow. The most useful level is Executed, but this takes as long as it takes to execute/evaluate the query.

      When timing a query you should keep in mind that the query performance will vary based on how much the JIT compiler has compiled the code (C1 vs C2) and based on what is or isn't cached in memory. If Timed explanations are considerably slower than Executed explanations the overhead with timing the query may be large on your system and should not be trusted.

      WARNING: This method is experimental and is subject to change or removal without warning. Same goes for the returned explanation. There is currently only partial support for this method in RDF4J and and UnsupportedOperationException where support is lacking.

      Specified by:
      explain in interface Query
      level - The explanation level that should be used to create the explanation. Choose between: Unoptimized (as parsed without optimizations) , Optimized (as is actually going to be used), Executed (as was executed/evaluated, including some real performance metrics), Timed (as was executed/evaluated including all real performance metrics). Executed and Timed level can potentially be slow.
      The explanation that we generated, which can be viewed in a human readable format with toString(), as JSON or as a simplified query plan object structure.