On 21/09/2020 15:27, Jenson Joseph wrote:
Thanks.
That explains a lot. Like why the difference in the size variable of the graphs
only includes the new statements and not implied ones.
Knowing this I have 2 options, run the listStatements command every time
there’s changes or only use forward chaining, but that one is limiting.
Do you think a 3rd option is viable where I create a new InfModel class that
takes this into account and somehow traces throw and keeps a cache of those
changes from the listStatement process, notifying the difference?
I guess it would be possible to construct such a wrapper Graph with a
cache and a notifier on triples which hadn't been cached before.
However, it would very inefficient and would only notify based on
whatever queries had been run.
If you need some notification of all inferences then I would have
thought that pure forward chaining would be the way to go.
Dave
Sent from my iPhone
On Sep 21, 2020, at 6:21 AM, Dave Reynolds <[email protected]> wrote:
I don't believe there's a custom notification arrangement for InfModels so
indeed you'd have to attach the listener to both the base model and the
deductions model.
For pure forward chaining rules that should be sufficient.
If you are using backward chaining rules, or the hybrid rule system (as used
for the all the default configurations for RDFS and OWL), then it's not
possible to get notifications for everything. In those setups then some of the
triples you see from listStatements have been implicitly generated on-demand
prompted by the query pattern and are never materialized or stored anywhere and
so can't trigger a listener.
Dave
On 20/09/2020 15:13, Jenson Joseph wrote:
HI,
I'm hoping I could get some help on this. I have an InfModel that I add a
listener to where I'm looking for all changes to the model, whether it was
inferred or not. On the model, I only get notified of changes that were
directly added, inferred changes are not notified. I switched to listening to
the deductions model and I don't get any notifications when I add new
statements.
I tried using combinations of the .rebind, .reset, .prepare functions with no
luck and I searched the internet on this with no luck.
I know the inferences are being made because they show up if I list the
statements of the inference model. I would like to know if it is currently
possible to have a listener that receives all changes made to n InfModel. The
reason for this is I want to keep track of the incremental changes and perform
queries on a small subset of the model. If I do the queries on the entire model
it would be more expensive while returning redundant results that have already
been seen and processed.
If this is an expected use case in Jena, that's handled differently I'm open to
hearing about that but I would love to have this meticulous listener within the
InfModel if you can help me figure that out.
Thanks,
Jenson
