Nicolas: It is important to understand why would you like RDF into JavaBeans. I mean in that case, a regular java application with RDBMS would also do the job or? So, if you consider for a second, you would have Javabeans being the objects updated by the application, internally you want to convert them to RDF and store them in a triple store. The architecture, however correct, sounds clunky unless there is a deep reason to have such an architecture and not intuitive.
I agree with Martynas, RDF opens a lot more possibilities. To answer the questions 1) Are there good practice or some DAO to design ? As mentioned above, what benefit do you get converting Javabeans to RDF? If no benefit, then stick to one paradigm and keep it simple!! 2) In term of performances, is it better to use ARQ (sparql) OR jena ontologie API ? For getting bulk information out, my experience has been SPARQL is better. (3) is it a good choice to store all in a triple store ? (versus traditional relational databases) ) Storing things in a triple store is better, in RDBMS you may end up using Jena SDB to store triples in RDBMS which gets clunky and slow. On Wed, Jan 7, 2015 at 5:53 AM, Martynas Jusevičius <[email protected]> wrote: > Nicolas: fair enough. However you should know that by simply replacing > the relational DB with a triplestore while using the same > object-oriented programming approach you're not getting even half of > the advantages of semantic technologies. RDF opens possibilities for > new software design patterns. > > On Tue, Jan 6, 2015 at 9:37 PM, Nicolas Paris <[email protected]> wrote: > > Martynas : Thanks for the link. Maybe your solution is excellent, but > > I don't want to lose me : classical MVC, is a security for me and the > > project. > > > > Olivier : The Elmo documentation is great. Do you think my application > > could be done with sesame ? I mean, sesame has a triple store, a > > reasoner, and looks like having a javabeans system much advanced than > > jena/PA4RDF have ? > > Anyway, jena/PA4RDF can actually do the job ; the documentation for > > PA4RDF is just really poor. > > Nicolas PARIS > > > > > > 2015-01-06 10:48 GMT+01:00 Olivier Rossel <[email protected]>: > >> Martynas, > >> > >> that is a bit off-topic but maybe you could organize a webinar so you > >> can show us some features of graphityhq. > >> > >> Nicolas: > >> > >> honestly, i know not very much about PA4RDF, > >> I use Elmo (rebranded as AliBaba) : > >> > http://sourceforge.net/projects/sesame/files/AliBabaElmo/1.5/openrdf-elmo-1.5.zip/download > >> > >> There is a nice user guide in the zip file, that gives a lot of details > >> about how to annotate beans so the persistence is transparent. > >> I think inheritance is explained too. > >> > >> On Tue, Jan 6, 2015 at 2:29 AM, Martynas Jusevičius > >> <[email protected]> wrote: > >>> Nicolas, > >>> > >>> I suggest you also take a look at Graphity Client: > >>> https://github.com/Graphity/graphity-client > >>> > >>> You don't really need an object layer representing your RDF classes > >>> above Jena, it is a bottleneck. You can express both the webapp > >>> structure and the instance data as RDF, and define a mapping from HTTP > >>> access to RDF state changes over SPARQL. > >>> > >>> Here's an example of how that structure (sitemap ontology) looks like: > >>> > http://lists.w3.org/Archives/Public/public-declarative-apps/2015Jan/0000.html > >>> > >>> Here's an example of an editing interface: > >>> > http://linkeddatahub.com/bibframe/instances?mode=http%3A%2F%2Fgraphity.org%2Fgc%23CreateMode > >>> > >>> Disclaimer: I'm the main developer. > >>> > >>> > >>> Martynas > >>> graphityhq.com > >>> > >>> On Mon, Jan 5, 2015 at 9:07 PM, Nicolas Paris <[email protected]> > wrote: > >>>> Thanks for answers ! > >>>> > >>>> - About http://callimachusproject.org/ : interesting but I have to > >>>> create application from scratch, because very specific > >>>> > >>>> - About PA4RDF : It seems very interessant. Any other tutorial, > >>>> related post or tip ? > >>>> Olivier, what do you exactly mean by "a bean <-> graph mapper" ? > >>>> I generate an OWL ontology, that is my structure of data. I will > >>>> modelise beans inspiring this structure. Say owl properties will be > >>>> java class properties. And RDF class's inheritance will be mapped to > >>>> java inheritance. Do you agree ? > >>>> However, it appears that the POJO class of PA4RDF limits the > inheritance. > >>>> The example here > >>>> http://pa4rdf.sourceforge.net/examples/concreteClassSubject.html > >>>> could feet with user <- student inheritance ? Or will I have to > >>>> duplicate code for Teacher & Student as they inherite from User ? > >>>> > >>>> Thanks again for this link Olivier ! > >>>> Nicolas PARIS > >>>> > >>>> > >>>> 2015-01-05 15:44 GMT+01:00 Olivier Rossel <[email protected]>: > >>>>> There was a discussion some weeks ago about PA4RDF. > >>>>> It might be a good starting point, in you think a bean <-> graph > mapper > >>>>> could be useful in your case. > >>>>> > >>>>> Also http://callimachusproject.org/ could be another interesting > >>>>> project to investigate in your case. > >>>>> > >>>>> On Mon, Jan 5, 2015 at 2:41 PM, Nicolas Paris <[email protected]> > wrote: > >>>>>> Hello, > >>>>>> > >>>>>> I am creating a web semantic application, were persistant data is > all > >>>>>> stored in triple store (TDB). > >>>>>> I mean, users(foaf), parameters etc. > >>>>>> This application is an e-learning application, with exercices > >>>>>> proposition based on reasonners. > >>>>>> > >>>>>> I want to use a classic MVC design pattern (jsp / servlets / > javabeans). > >>>>>> So a javabeans user, teacher, and student with heritage. > >>>>>> My naïve aproach would be to initialise jbeans from TDB, using jena > >>>>>> model getInstance etc. Or Sparql Querys with ARQ > >>>>>> and my setters will do both : > >>>>>> - set jbeans propertys > >>>>>> - modify triple (dataset jena setProperty ; dataset commit , OR > SPARQL querys) > >>>>>> > >>>>>> Example bad pseudo-code: > >>>>>> Class student extends user { > >>>>>> private Integer age; > >>>>>> private Ressource student = myModel.getIndividual( > >>>>>> "http://www.myexample.com/mySchema#student1"; ); > >>>>>> > >>>>>> public void setAge(Integer age){ > >>>>>> this.age = age; //modify jbeans property > >>>>>> student.setPropertyValue("http://www.myexample.com/mySchema#age > ","1^^integer") > >>>>>> # modify TDB valyue > >>>>>> } > >>>>>> > >>>>>> } > >>>>>> > >>>>>> > >>>>>> 1) Are there good practice or some DAO to design ? > >>>>>> 2) In term of performances, is it better to use ARQ (sparql) OR jena > >>>>>> ontologie API ? > >>>>>> (3) is it a good choice to store all in a triple store ? (versus > >>>>>> traditional relational databases) ) > >>>>>> > >>>>>> Thanks a lot > >>>>>> > >>>>>> > >>>>>> > >>>>>> Nicolas PARIS >
