On 02/01/17 09:23, George News wrote:
On 31/12/2016 16:42, Andy Seaborne wrote:
sometime when concurrently calling the webservice
Having code fragment does not help here - could it be that one
request is doing
Individual.isClass()
while another is closing the model?
if so, why is one request closing a shared object? Either keep the
object open, or make a fresh object per request.
Andy
I know it's difficult.
Hmmm.
But could you please have a look at the way I'm
creating the MyOntModelSpec. Is it correct? If yes, then is the model
correctly created that spec?
Insufficient information to tell.
Does your "etc/my.owl" switch on model caching?
Does the code you haven't shown us close your OntModels somewhere?
There's no explicit close in the fragments you've posted but the
exception suggests you are doing close somewhere - directly or indirectly.
Your MyOntModelSpec.getInstance is sharing a global singleton instance
which in turn is sharing the FileManager clone that you set up. If you
have caching switched on in your config then the cached imports will be
shared across your models. If you close() one of those OntModels I think
that will close all the imported submodels including those in the shared
FileManager cache which could lead to the problem you see.
None of your code fragments have any sign of locking or synchronization
so there is at least a race condition in MyOntModelSpec.getInstance
which might result in your having multiple MyOntModelSpec instances but
that seems unlikely to be the problem.
However, since FileManager caching doesn't look particularly thread-safe
to me then unless you are doing your own synchronization around all the
operations that touch it that could also cause problems.
Dave
