On a second thought, since our code is only reading from the models, it is
probably easier and safer just to clone the shared model into a per-request
copy, and keep the code as it is.
Is the following code the fastest way to do it? Is add() expensive?
OntModel ontModel =
OntDocumentManager.getInstance().getOntology(ontologyURI, ontModelSpec);
OntModel clonedModel = ModelFactory.createOntologyModel(ontModelSpec);
clonedModel.add(ontModel);
On Sat, Jul 16, 2016 at 3:47 PM, Martynas Jusevičius <marty...@graphity.org>
wrote:
> Hey,
>
> in our webapp, all objects are created per-request, except ontologies
> stored in a shared OntDocumentManager, that are accessed like this:
>
> OntDocumentManager.getInstance().getOntology(ontologyURI, ontModelSpec);
>
> This has caused some ConcurrentModificationExceptions. I have read the
> https://jena.apache.org/documentation/notes/concurrency-howto.html
> document, and wanted to check if I get this right.
>
> Basically, every operation and iterator on a shared OntModel has to be
> in a critical section? Even if it's indirect and called on an OntClass
> from the OntModel:
>
> OntModel ontModel =
> OntDocumentManager.getInstance().getOntology(ontologyURI,
> ontModelSpec);
> ontModel.enterCriticalSection(Lock.READ);
> try
> {
> OntClass ontClass = ontModel.getOntClass("http://some/class";);
> NodeIterator it = ontClass.listPropertyValues(GC.supportedMode);
> try
> {
> while (it.next)
> ...
> }
> finally
> {
> it.close();
> }
> }
> finally
> {
> model.leaveCriticalSection() ;
> }
>
> Is that correct?
>
> Martynas
