[[ Cross-post - prefer replies to dev@commons ]] Each of the Common RDF implementations come with a RDFTermFatory
http://stain.github.io/incubator-commonsrdf/integration/org/apache/commons/rdf/api/RDFTermFactory.html On a classical flat classloader the implementations of this factory can be discovered with java.util.ServiceLoader So if you have say a JsonLdRDFTermFactory you can call .createTriple() etc - and it would be backed by that implementation. As mentioned the marker interfaces will allow you to later on get hold of the wrapped object, e.g. to do some RDFS reasoning on a Jena Model or to parse it to a serializer. But what if you already have a 'native' object, e.g. a org.eclipse.rdf4j.model.Statement - and you want to convert it/adapt it to the corresponding Commons RDF API Triple? Obviously there would not be a general interface for this (without using ?-generics) as each backend implementation would have different (so far unrelated) types - but we can at least agree on the common style? In http://stain.github.io/incubator-commonsrdf/integration/org/apache/commons/rdf/rdf4j/RDF4JTermFactory.html I suggests as*() adapter methods like: RDF4JQuad asQuad(org.eclipse.rdf4j.model.Statement RDF4JTriple asTriple(org.eclipse.rdf4j.model.Statement statement) RDF4JTerm asRDFTerm(org.eclipse.rdf4j.model.Value value) RDF4JDataset asRDFTermDataset(org.eclipse.rdf4j.repository.Repository repository) RDF4JGraph asRDFTermGraph(org.eclipse.rdf4j.model.Model model) RDF4JGraph asRDFTermGraph(org.eclipse.rdf4j.repository.Repository repository) but also the inverse converters: org.eclipse.rdf4j.model.Value asValue(RDFTerm term) org.eclipse.rdf4j.model.Statement asStatement(TripleLike<BlankNodeOrIRI,IRI,RDFTerm> tripleLike) (These will unpack the wrapped value if it's an RDF4JTerm - or create a new RDF4J native instance if it's a "foreign" class) Questions: a) Do these adapter methods belong in the RDFTermFactory or should there be a new family of 'adaptor factories'? (e.g. the Jena Factory b) What should we call these methods? Is as*() appropriate or should they more closely match the createTriple() etc methods from RDFTermFactory? With asSomething() I wanted to hint of adaptation - rather than 'convert' or 'create' - but without having to commit to adaptation with adapt() or wrap(). Now sometimes the implementations use the same class name as Commons RDF (e.g. Quad or Graph). Code-wise this is not too hard to deal with (avoid importing either), but it means it can get more confusing for downstream API users who do auto-complete and then don't know what direction they are adapting. c) Should the adapter methods have short names (e.g. asGraph()) - distinguished by type polymorphism and javadocs - or more verbose to show which particular return-type you get? (e.g. asJenaGraph() and asCommonsRDFGraph()) ) d) Do we need to rename RDFTermFactory to RDFFactory (or just RDF) ? -- Stian Soiland-Reyes http://orcid.org/0000-0001-9842-9718
