Sergey, Let me see if I understand what you are saying. Are you saying this:
* We could implement the .api2 CP as shown below, but it will be difficult to implement in it many aspects of SPARQL because the semantics can¹t be expressed in the .api CP using .api.IFilter. If yes, then I was thinking was different. I was not assuming that .api.IFilter semantics were sufficient to express the SPARQL semantics directly. I was, however, assuming that the upper .api2 CP may in some cases have to read (using lower .api CP) many, most, and sometimes ALL (!) entities from the lower .api CP and perform the SPARQL WHERE filtering algorithms itself. And this is why I was saying that the performance may be very bad when this two layer approach is taken. I¹m looking for a solution that allows the old .api to be maintained and to be able to reuse these ³old² CPs by adapting them with the upper .api2 CP. If the performance is too bad, then the developer can implement a ³native² (not two layered) CP using .api2. --Paul On 10/15/09 11:27 AM, "Sergey Lyakhov" <[email protected]> wrote: > Paul, > >> > Do you think it is practical to implement this: >> > +----------------------------------------+ >> > | Upper CP that implements .idas.api2 | >> > | SPARQL api but read/writes ³raw² | >> > | entities/attributes from lower CP | >> > +----------------------------------------+ >> > +----------------------------------------+ >> > | Lower CP implements existing .idas.api | >> > +----------------------------------------+ > > I think we are able to implement basic aspects of SPARQL which will satisfy > our requirements. However it will be difficult to implement many aspects of > SPARQL such as FILTER functions in WHERE clause (moreover, there is no any > equivalent of those functions in idas.api.IFilter). For example, if I want to > use regex(..) SPARQL FILTER function in Upper CP, I'll need first select all > entities from old CP, and than make additional check selecting entities which > conform to the regexp. > > Thanks, > Sergey Lyakhov >> >> ----- Original Message ----- >> >> From: Paul Trevithick <mailto:[email protected]> >> >> To: higgins-dev <mailto:[email protected]> >> >> Cc: Vadym Synakh <mailto:[email protected]> ; Paul Trevithick >> <mailto:[email protected]> ; Igor Tsinman <mailto:[email protected]> >> >> Sent: Thursday, October 15, 2009 4:31 PM >> >> Subject: Re: [higgins-dev] IdAS changes proposal >> >> >> Sergey, >> >> Hmmm, this is a tough one. We don¹t want to lose the investments in the >> existing CPs (the old .idas.api). Yet we don¹t want to create a burden for >> new CP developers. While we mull this over, I have a question. Do you think >> it is practical to implement this: >> >> >>> +----------------------------------------+ >>> | Upper CP that implements .idas.api2 | >>> | SPARQL api but read/writes ³raw² | >>> | entities/attributes from lower CP | >>> +----------------------------------------+ >>> +----------------------------------------+ >>> | Lower CP implements existing .idas.api | >>> +----------------------------------------+ >> >> If so, then we could maintain both the lower and the upper APIs. Any CP that >> didn¹t want to support the .api2 (upper api) wouldn¹t have to, there because >> they could use the upper ³adapter² CP. The result might be very slow, but at >> least it (might) work. And if good SPARQL performance was required, then the >> CP would be force to do a native implementation of .idas.api2. >> >> [One really interesting benefit of implementing SPARQL is that with the >> above adapter plus a web service front end, we can expose any IdAS data >> source as a SPARQL endpoint. Then we¹d have XDI and SPARQL endpoints for the >> Attribute Service. The Linked Object Data (LOD) semweb folks are creating >> lots of SPARQL endpointswe¹d dovetail with these efforts. >> >> --Paul >> >> >> >> On 10/15/09 6:23 AM, "Sergey Lyakhov" <[email protected]> wrote: >> >> >>> Paul, >>> >>> Sorry for delay. >>> >>>> > 3. Jim Sermersheim invented IFilter because we needed something and >>>> SPARQL wasn¹t yet established. Now that it is, I wonder if we shouldn¹t >>>> give it another look >>> >>> It would be very convinient to use SPARQL for RDF-based context providers >>> (like jena CP). However it would be hard to implement all aspects of SPARQL >>> for context providers which are not based on RDF (JNDI, XML, Hibernate >>> etc.). >>>> > When you go to make these changes, it will be critical to load into your >>>> workbench every possible context >>>> > provider that you can find so that you can fix them so that they don¹t >>>> all break. >>> >>> It will take a lot of work to implement new filter/model for all providers. >>> So, I suppose there is a sence to put new IdAS interfaces into a new >>> project (like org.eclipse.higgins.idas.api2) and than fix all providers to >>> support these new interfaces. What do you think about this? >>> >>> Thanks, >>> Sergey Lyakhov >>> >>>> >>>> ----- Original Message ----- >>>> >>>> From: Paul Trevithick <mailto:[email protected]> >>>> >>>> To: higgins-dev <mailto:[email protected]> >>>> >>>> Cc: Vadym Synakh <mailto:[email protected]> ; Paul Trevithick >>>> <mailto:[email protected]> ; Igor Tsinman >>>> <mailto:[email protected]> >>>> >>>> Sent: Monday, September 28, 2009 3:11 AM >>>> >>>> Subject: Re: [higgins-dev] IdAS changes proposal >>>> >>>> >>>> Sergey, >>>> >>>> My responses: >>>> >>>> >>>> 1. agree >>>> 2. agree >>>> 3. Jim Sermersheim invented IFilter because we needed something and >>>> SPARQL wasn¹t yet established. Now that it is, I wonder if we shouldn¹t >>>> give it another look >>>> 4. (4.1): short answer: no. Longer answer: cdm.owl is an attempt to >>>> approximate in owl concepts that cannot be directly operationalized in >>>> real RDF/OWL based systems. Only higgins.owl should be imported and >>>> used. Cdm.owl is just an attempt at explanation. It can be ignored. (4.2) >>>> A lot of OWL URLS end in .owl, but it isn¹t a firm requirement or >>>> convention. >>>> >>>> When you go to make these changes, it will be critical to load into your >>>> workbench every possible context provider that you can find so that you >>>> can fix them so that they don¹t all break. >>>> >>>> --Paul >>>> >>>> On 9/23/09 12:07 PM, "Sergey Lyakhov" <[email protected]> wrote: >>>> >>>> >>>> >>>>> Paul, >>>>> >>>>> I suppose, cdm:entityId is redundant and we can use rdf:ID instead. As a >>>>> result: >>>>> >>>>> 1.1. In this case IEntity.getEntityID() will retun rdf:ID. >>>>> 1.2. In case of blank entity (previously known as a complex value) it >>>>> should return null. >>>>> 1.3. entityId attribute will be eliminated. >>>>> >>>>> I suppose we need to do the following changes to IdAS interfaces to be >>>>> compatible with CDM: >>>>> >>>>> 2.1. BlankEntity class has been eliminated from cdm.owl. So, I suppose >>>>> we need to do the same for IdAS interfaces and replace IBlankEntity with >>>>> IEntity (eliminate IBlankEntity interface). >>>>> >>>>> Because there is no any difference between entity and complex value, we >>>>> can define the following: >>>>> >>>>> 2.2. If Entity has been created by IContext.addEntity(entityType, >>>>> entityID) method, it should always have entityID (should not be a blank >>>>> entity). In other words, a unique value should be generated by a context >>>>> and used as entityId, if no entityId passed. >>>>> 2.3. If Entity has been created by IAttribute.addValue(URI) method, it >>>>> should be a blank entity. >>>>> 2.4. If Entity has been added by IAttribute.addValue(IAttributeValue) it >>>>> should be the same type as passed entity. If passed entity is a blank >>>>> entity, new blank entity should be created as a copy of passed, >>>>> otherwise a reference to the existent (non blank) entity should be >>>>> created. >>>>> 2.5. When Entity is deleted, all its subentities which are a blank >>>>> entity should be deleted too. >>>>> >>>>> Also we need more flex IFilter API: >>>>> >>>>> 3.1. IFilter should be able to query both types of entities as blank as >>>>> usual. >>>>> 3.2. IFilter should be able to query a separate value (entity or simple >>>>> value) of any nesting level, not only direct attributes of Entity. >>>>> >>>>> Also I have some notes about CDM: >>>>> >>>>> 4.1. CDM.owl contains entityRelation and contextRelation object >>>>> properties. Do we need to reflect them in IdAS interfaces? >>>>> 4.2. Namespase of cdm.owl >>>>> http://www.eclipse.org/higgins/ontologies/2008/6/cdm.owl ends with .owl. >>>>> Is it correct? >>>>> >>>>> Thanks, >>>>> Sergey Lyakhov >>>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> higgins-dev mailing list >>>> [email protected] >>>> https://dev.eclipse.org/mailman/listinfo/higgins-dev >>>> >> >> >> >> >> >> >> _______________________________________________ >> higgins-dev mailing list >> [email protected] >> https://dev.eclipse.org/mailman/listinfo/higgins-dev >>
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