[STANBOL-580] Remove Dependency for "stanbol.commons.web.sparql" to "stanbol.contenthub.servicesapi"

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: contenthub-0.10.0
• Component/s: Commons, Contenthub
• Assignee: Suat Gonul
• Reporter: Rupert Westenthaler
• Created: 07/Apr/12 13:50
• Updated: 17/Jul/13 15:18
• Resolved: 31/May/12 10:55

Description

Commons Module MUST NOT depend on any other Stanbol modules other than Commons. Because of that the "org.apache.stanbol.commons.web.sparql" MUST NOT depend on "org.apache.stanbol.contenthub.servicesapi"

Possible Solution:

I would suggest to use the Whiteboard pattern to register TripleCollections that should be exposed by SPARQL. The SparqlEndpointResource could than lookup all NamedGraphs - the registered TripleCollections - by using the BundleContext or a ServiceTracker.

Additional Notes:

• This solution would allow to expose multiple query-able RDF graphs via {stanbol}

  /sparql

• SPARQL already allows to specify the graph to query by using the "default-graph-uri" parameter. This parameter should be supported by "stanbol.commons.web.sparql" to allow requests to select a specific registered TripleCollection for the query
• If no "default-graph-uri" is specified the TripleCollection registered with the higest "service.ranking" (if multiple lowest "service.id") is used to execute the query

The following properties are supported for ServiceRegistrations of TripleCollections:

• "graph.uri" (requried) : The URI of the graph. This is the same as used with the TcManager
• "service.ranking" : If not than '0' will be used as default
• "graph.name" : The name of the graph. Human readable name intended to be used in the UI of the SparqlEndpointResource (dropdown box to select one of the registered TripleCollections)
• "graph.description" : A human readable description providing additional information about the RDF graph.

NOTE: I would not recommend to directly use the TcManager because

1. we might not want to make all grpahs public available
2. we might want to publish graphs hold in-memory that are not registered with any TcManager (e.g. the configuration of the Stanbol instance)

If this proposal is accepted I would recommend to copy this description to an own sub-task

Issue Links

• is related to: STANBOL-588 Commons modules should not have dependencies outside of commons