Thank you for the detective work and sorry for not responding to the
other email. I read it but didnt have time to follow up on it.
I think that add should handle this since createService is intended to
be simple.
As for the lock issues I expect that it was implemented poorly in that
database. But I dont know too much about it. Perhaps when we make
the change so that the catalog is persisted rather than being all lazy
loading we will make it easier to implement services so we dont have
so many locking problems.
Jesse
On 18-Dec-08, at 11:32 AM, Ugo Taddei wrote:
Hello,
for the archives, or to whom it may concern. I didn't find the
problem directly, but I tracked this down to something very weird.
I basically want to add a new layer to a map. This is often a layer
DB layer from a table that gets created dynamically.
The workflow where this happens is:
1) Find a service (for a DB). Done with the example code from the
wiki (http://udig.refractions.net/confluence/display/DEV/2+Catalog)
for( IService service : serviceFactory.createService( params ) ){
try {
CatalogPlugin.getDefault().getLocalCatalog().add( service );
// skip code to find the chosen resource, i.e. DB table
}catch (IOException couldNotConnect ){}
}
2) Add new resource to a map. Everything works.
3) A new Table/View is created on the DB. udig gets notified of this
and...
4) ...runs the same code as in (1), but look for newly created table
5) New table is found, service is added (again?)
6) Application behaves erratically: layer shows up on the list, but
has no data (because of NullGeoResource)
The problems seems to be
CatalogPlugin.getDefault().getLocalCatalog().add( service );
The DB is the same, only a new table has been created. I *think* the
catalog holds two services, where there should be a single one.
I fixed the problem by keeping a reference to the first service
being added. Before I run the for loop again, I remove the service.
So either serviceFactory.createService( params ) shouldn't return
two instances of the same service, or Catalog.add( service ) should
handle the case where the service has already been added. (It *is*
the same DB, so it should be a single instance of the service,
shouldn't it?)
Anyway, I might be completely wrong. This was very difficult to
find. And I think I've got it running, but for
OracleServiceImpl.lock() problems. (Which seem to be completely
unrelated to all of this, as I've had lock problems running udig
trunk against the DB, and without any comlexities of tables that get
created *after* the catalog has been created. That is, lock problems
do appear when udig is run as a "normal" product".)
If all of this makes sense to anyone, and if anyone wants more info,
please let me know.
Cheers,
Ugo
Ugo Taddei wrote:
Hello,
I'm trying to programatically add a layer (from an Oracle DB).
Though the code works in most circumstances, sometimes I see my
layer with an OracleGeoResource (just before it gets added in
AddLayersCommand.run(IProgressMonitor) ), have its georesource
turned into a NullGeoResource(http://NULL).
The layer comes from an oracle view that gets created dynamically.
The point is, when I run the code again, the layer gets added.
Am I missing something, like telling the Catalog to synchronize?
This is a tough one. I've tracked the problem down to
LayerFactoryImpl.createLayer(IGeoResource) but I'd like to make
sure I'm not missing anything before I dig further.
BTW, in LayerFactoryImpl.createLayer(IGeoResource), the line
layer.setGeoResource(preferredResource);
might yield
LayerImp.geoResource = null;
Does anyone want to have that? (Perhaps that's the reason for my
problem?)
Thanks in advance,
Ugo
--
Ugo Taddei
Fraunhofer Institut Intelligente Analyse- und Informationssysteme
(FhG IAIS)
http://www.iais.fraunhofer.de
Department Knowledge Discovery - IAIS.KD -
Working Group Spatial Decision Support
http://www.iais.fraunhofer.de/kd.html
phone (+49)2241-14-2184 fax (+49)2241-14-2072
Schloss Birlinghoven, D-53754 Sankt Augustin, Germany
_______________________________________________
User-friendly Desktop Internet GIS (uDig)
http://udig.refractions.net
http://lists.refractions.net/mailman/listinfo/udig-devel
_______________________________________________
User-friendly Desktop Internet GIS (uDig)
http://udig.refractions.net
http://lists.refractions.net/mailman/listinfo/udig-devel
