To me, it seems unfortunate to make the Resource do all the work, and make it more than the subject of triples. Some labeled property graphs define an OGM (Object/Graph Mapping). I wonder whether that concept has any bearing here.
Anyway, I've wished for an OGM sort of mapping to a POJO for awhile. One annotation to say its a Jena resource. Another Annotation to say which method returns its URI, and give an optional prefix. Additional annotations to label setters or properties by predicate - this would not be too bad coupled with org.apache.jena.vocabulary. Might need different annotations for object properties and data properties. On Sun, Apr 7, 2019 at 7:54 AM Claude Warren <[email protected]> wrote: > Thomas, > > I think that PA4RDF does/did what you want to do > (https://github.com/Claudenw/PA4RDF) Basically, you define FoafPerson > as an interface and annotate the getX methods to identify the > properties that identify the value. Something like: > > {noformat} > @Subject(namespace = "http://xmlns.com/foaf/0.1/";, > class="http://xmlns.com/foaf/0.1/FoafPerson";) > public interface FoafPerson { > > String getName(); > @Predicate > vod setName( String name ); > boolean hasName(); > } > {noformat} > > Create an use an entity manager by requesting > > {noformat} > FoafPerson fp = entityManager.read( resource, FoafPerson.class ); > {noformat} > > Will create fp as an instance of FoafPerson backed by the specified > resource. > > PA4RDF used dynamic proxies so it can create objects that are > combinations of objects. All objects returned implement > ResourceWrapper so you can allways call fp.getResource() to get the > resource back from the object. > > Claude > > Note: If you decide to go this route use the 1.1 version as the > current head branch is a different implementation and has some > significant issues. > > > > On Wed, Apr 3, 2019 at 8:33 AM Thomas Francart > <[email protected]> wrote: > > > > 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 > > > > -- > I like: Like Like - The likeliest place on the web > LinkedIn: http://www.linkedin.com/in/claudewarren >
