Hello Le mar. 2 avr. 2019 à 21:54, ajs6f <[email protected]> a écrit :
> Personality and related types are described briefly here: > > > https://jena.apache.org/documentation/notes/jena-internals.html#enhanced-nodes Thanks, this describes what I would like to do : ``` 1. define an interface I for the new enhanced node. (You could use just the implementation class, but we've stuck with the interface, because there might be different implementations) 2. define the implementation class C. This is just a front for the enhanced node. All the state of C is reflected in the graph (except for caching; but beware that the graph can change without notice). 3. define an Implementation class for the factory. This class defines methods canWrap and wrap, which test a node to see if it is allowed to represent I and construct an implementation of Crespectively. 4. Arrange that the personality of the graph maps the class of I to the factory. At the moment we do this by using (a copy of) the built-in graph personality as the personality for the enhanced graph. ``` > > > I know little about them, but to my understanding, that is not a > well-developed part of Jena and the technical ideas there are not under > active development. You are noticing that when you find the constructor odd > and hard to fill; that's in part because it mixes Jena's API (Resource, > Statement, Model, etc.) with its SPI (Node, Triple, Graph, etc.). > > Could you tell us a little more about what you are doing? Why do you want > to extend Resource? > I'd like to do : 1. Define an interface that extends Resource : ``` public interface FoafPerson extends Resource { public String getName(); } ``` 2. Define an implementation : ``` public interface FoafPersonImpl implements FoafPerson extends ResourceImpl { // constructor : how will this be called ??? public FoafPersonImpl(Node node, EnhGraph graph) { super(node, graph); } @Override public String getName() { return this.getProperty(FOAF.name).getString(); } } ``` 3. Define an Implementation class : ... here, I am lost 4. Maps the class I to the factory : ... here, I am lost 5. Use this; I'd like to be able to do : ``` Model m = ...; Resource r = ...; // obtain a view on the Resource as a Foaf Person : FoafPerson person = r.as(FoafPerson.class); System.out.println(person.getName()); ``` Any help in filling the blanks above would be appreciated ! Thanks Thomas > ajs6f > > > On Apr 2, 2019, at 3:48 PM, Thomas Francart <[email protected]> > wrote: > > > > Hello > > > > I would like to declare data structure with an Interface that extends > Jena > > Resource and its implementation that extends Jena ResourceImpl in the > same > > way as > > > https://github.com/TopQuadrant/shacl/blob/a3f54abeffc691ff0b15bee7f049741eb6e00878/src/main/java/org/topbraid/shacl/model/SHShape.java > > (interface) and > > > https://github.com/TopQuadrant/shacl/blob/a3f54abeffc691ff0b15bee7f049741eb6e00878/src/main/java/org/topbraid/shacl/model/impl/SHShapeImpl.java > > (implementation, which indirectly extends ResourceImpl). > > Is it a common and good practice ? > > > > The constructor of the implementation takes as an input (Node node, > > EnhGraph graph). > > I don't know how to obtain or build these Node and EnhGraph from plain > > Resource / Model I am used to. I will be working with memory or > TDB-backed > > Models, if that matters. How can I obtain or build these so that I can > call > > the constructor of my data structure extending ResourceImpl, with a Node > > and EnhGraph instance ? > > > > I feel this could be related to "Personality<RDFNode>", as can be seen at > > > https://github.com/TopQuadrant/shacl/blob/76257beb501381542361b52363329999363753ff/src/main/java/org/topbraid/shacl/model/SHFactory.java > , > > where RDF classes URI are associated to the corresponding Java classes. > > > > I am lost here, could someone shed some light on this design pattern ? > > > > Thanks > > Thomas > > > > -- > > > > *Thomas Francart* -* SPARNA* > > Web de *données* | Architecture de l'*information* | Accès aux > > *connaissances* > > blog : blog.sparna.fr, site : sparna.fr, linkedin : > > fr.linkedin.com/in/thomasfrancart > > tel : +33 (0)6.71.11.25.97, skype : francartthomas > > -- *Thomas Francart* -* SPARNA* Web de *données* | Architecture de l'*information* | Accès aux *connaissances* blog : blog.sparna.fr, site : sparna.fr, linkedin : fr.linkedin.com/in/thomasfrancart tel : +33 (0)6.71.11.25.97, skype : francartthomas
