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  1. Apache Jena
  2. JENA-1069

Simpify the internal naming of the default graph (Quad constants)



    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Won't Fix
    • Affects Version/s: Jena 3.0.0
    • Fix Version/s: None
    • Component/s: ARQ
    • Labels:


      There are two different constants for the default graph for what seemed at the time, slightly different situations. The idea was that quads from the default graph of a dataset would be Quad.defaultGraphIRI and quads created by parsers, would be Quad.defaultGraphNodeGenerated. The idea was that the output of the parser was "default graph" but it was being redirected into a named graph. This does not now seem useful.

      Quad.defaultGraphIRI = <urn:x-arq:DefaultGraph>

      Quad.defaultGraphNodeGenerated = <urn:x-arq:DefaultGraphNode>

      In SPARQL, the application is using GRAPH <urn:x-arq:DefaultGraph>. Using <urn:x-arq:DefaultGraphNode> wil not work consistently.

      The proposal is to combine these two as Quad.defaultGraphIRI, possible migrate to Quad.defaultGraph, or even a class or enum for the graph naming constants.

      These constants should never have been written to disk in database, certainly not <urn:x-arq:DefaultGraphNode>, but just to make sure, the operation Quad.isDefaultGraph(Node) can take the old name into account for a release cycle.

      Nearly all the changes are in tests where the expected output has been explicitly written into test results.

      There is another, little used, constant – Quad.tripleInQuad – for when a triple is in a quad just to be transported around, meaning "meaningless", "unknown" or "doesn't matter". This would not change. It exists to be different from Quad.defaultGraphIRI.


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              • Assignee:
                andy Andy Seaborne
                andy Andy Seaborne
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