Hi Isley, Clerezza community
this seams to be related to an issue in the Clerezza SPARQL
implementation. I think the problem is that the "Jena <-> Clerezza"
Adapter enforces that subjects of triples need to be NonLiterals, but
the last statement of your Sparql Query. An assumption that MUST NOT
be true for SPARQL query results where resources in any position
(subject, predicate, object) can have any type (Literal, URI or
bNode).
This query
> SELECT * WHERE {
> <Target Person 1 URI> ?pf1 ?middle .
> <Target Person 2 URI> ?ps1 ?os1 .
> ?os1 ?ps2 ?middle .
> } LIMIT 10
does exactly that, as it uses values ( 'os1') of '<Target Person 2
URI> ?ps1 ?os1' as first argument (subject) for an second join '?os1
?ps2 ?middle'.
Would be nice if someone with more knowledge about the Clerezza SPARQL
implementation could look into that.
best
Rupert
On Fri, May 31, 2013 at 7:17 PM, Isley, Steven <sis...@prgs.edu> wrote:
> Hello everyone,
>
> I've been trying to integrate Apache Stanbol and Relfinder[1] (my two
> favorite demos to show people who have never heard of the semantic web). I
> ran into some problems with Relfinder that I think I fixed. It was using a
> different parameter name to specify the graph to use in the SPARQL query.
> After recompiling Relfinder to work with Stanbol, I've run into some other
> errors which may be Stanbol related.
>
> Relfinder tries to find paths through a dataset that link two nodes. I've
> uploaded an rdf data set to a clerezza managed site. The data consists of
> documents, their authors, and then some other information (such as an
> author's department, or a document's publish date). I've got about 500k
> triples.
>
> My version of Relfinder will find some links between nodes. Like if the two
> input nodes are people, it will find documents they both authored, or
> departments they both belong to. However, the more impressive searches result
> in an "Error 500 cannot convert {one of my URIs} to NonLiteral" (see end of
> email for full error message). Using firebug to monitor the network requests
> shows that this error occurs for all the searches that are supposed to return
> the more complicated results (Target Person 1 authored document X, also
> authored by person B, that authored document Y, that was also authored by
> Target Person 2)
>
> I spent some time playing with Stanbol's SPARQL endpoint, and the simplest
> example that reproduces the error is:
>
> SELECT * WHERE {
> <Target Person 1 URI> ?pf1 ?middle .
> <Target Person 2 URI> ?ps1 ?os1 .
> ?os1 ?ps2 ?middle .
> } LIMIT 10
>
> However, the following query works fine:
> SELECT * WHERE {
> <Target Person 1 URI> ?pf1 ?middle .
> <Target Person 2 URI> ?ps1 ?os1 .
> } LIMIT 10
>
> Note that these are simplified searches, the actual Relfinder queries are
> more complicated, and attempt to filter out literal values. See the very,
> very end of this email for the original query. Relfinder works fine on other
> SPARQL endpoints, like dbpedia's.
>
> Thanks for any insights you can offer on this problem. The help is much
> appreciated.
>
>
> --
> Steven Isley
> Ph.D. Candidate
> Pardee RAND Graduate School
> RAND Corporation
> ph: (310)393-0411 x6643
>
> -Steve Isley
>
> [1] http://www.visualdataweb.org/relfinder.php
>
>
> p.s. - if anyone else is trying to use RelFinder, I also ran into issues with
> CPU usage. Sometimes Stanbol would overrun the cpu limit on my server and
> would be silently killed. Took me a while to figure that one out! I managed
> to get around this using "unlimit cpu" - but the IT folks at my workplace
> will probably come down on me for that :)
>
> Error Output:
> <html>
> <head>
> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"/>
> <title>Error 500 cannot convert "{the rdfs:label for Person 1}" to
> NonLiteral</title>
> </head>
> <body><h2>HTTP ERROR 500</h2>
> <p>Problem accessing /sparql. Reason:
> <pre> cannot convert "{the rdfs:label for Person 1}" to
> NonLiteral</pre></p><h3>Caused by:</h3><pre>java.lang.RuntimeException:
> cannot convert "{the rdfs:label for Person 1}"to NonLiteral
> at
> org.apache.clerezza.rdf.jena.commons.Jena2TriaUtil.convertNonLiteral(Jena2TriaUtil.java:127)
> at
> org.apache.clerezza.rdf.jena.facade.JenaGraph.filter(JenaGraph.java:123)
> at
> org.apache.clerezza.rdf.jena.facade.JenaGraph.graphBaseFind(JenaGraph.java:151)
> at com.hp.hpl.jena.graph.impl.GraphBase.find(GraphBase.java:240)
> at
> com.hp.hpl.jena.graph.impl.GraphBase.graphBaseFind(GraphBase.java:260)
> at com.hp.hpl.jena.graph.impl.GraphBase.find(GraphBase.java:257)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterTriplePattern$TripleMapper.<init>(QueryIterTriplePattern.java:67)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterTriplePattern.nextStage(QueryIterTriplePattern.java:41)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterRepeatApply.makeNextStage(QueryIterRepeatApply.java:91)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterRepeatApply.hasNextBinding(QueryIterRepeatApply.java:52)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:66)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterBlockTriples.hasNextBinding(QueryIterBlockTriples.java:53)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:66)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIterSlice.hasNextBinding(QueryIterSlice.java:64)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:66)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:28)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:66)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:28)
> at
> com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:66)
> at
> com.hp.hpl.jena.sparql.engine.ResultSetStream.hasNext(ResultSetStream.java:57)
> at
> org.apache.clerezza.rdf.jena.sparql.ResultSetWrapper.<init>(ResultSetWrapper.java:39)
> at
> org.apache.clerezza.rdf.jena.sparql.JenaSparqlEngine.execute(JenaSparqlEngine.java:68)
> at
> org.apache.clerezza.rdf.core.access.TcManager.executeSparqlQuery(TcManager.java:272)
> at
> org.apache.stanbol.commons.web.sparql.resource.SparqlEndpointResource.sparql(SparqlEndpointResource.java:162)
> at
> org.apache.stanbol.commons.web.sparql.resource.SparqlEndpointResource.postSparql(SparqlEndpointResource.java:182)
> at sun.reflect.GeneratedMethodAccessor39.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:616)
> at
> com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
> at
> com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
> at
> com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
> at
> com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
> at
> com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
> at
> com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
> at
> com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1480)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1411)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1360)
> at
> com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1350)
> at
> com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
> at
> com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
> at
> com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
> at
> org.apache.felix.http.base.internal.handler.ServletHandler.doHandle(ServletHandler.java:96)
> at
> org.apache.felix.http.base.internal.handler.ServletHandler.handle(ServletHandler.java:79)
> at
> org.apache.felix.http.base.internal.dispatch.ServletPipeline.handle(ServletPipeline.java:42)
> at
> org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:49)
> at
> org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:78)
> at
> org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
> at
> org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
> at
> org.apache.stanbol.commons.httpqueryheaders.impl.QueryHeadersFilter.doFilter(QueryHeadersFilter.java:75)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:88)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:76)
> at
> org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
> at
> org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
> at
> org.apache.stanbol.commons.web.resources.ResourceServingFilter.doFilterHttp(ResourceServingFilter.java:148)
> at
> org.apache.stanbol.commons.web.resources.ResourceServingFilter.doFilter(ResourceServingFilter.java:91)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:88)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:76)
> at
> org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
> at
> org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
> at
> org.apache.stanbol.commons.security.auth.AuthenticatingFilter$1.run(AuthenticatingFilter.java:163)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAsPrivileged(Subject.java:537)
> at
> org.apache.stanbol.commons.security.auth.AuthenticatingFilter.doFilter(AuthenticatingFilter.java:159)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:88)
> at
> org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:76)
> at
> org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
> at
> org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
> at
> org.apache.felix.http.base.internal.dispatch.FilterPipeline.dispatch(FilterPipeline.java:48)
> at
> org.apache.felix.http.base.internal.dispatch.Dispatcher.dispatch(Dispatcher.java:39)
> at
> org.apache.felix.http.base.internal.DispatcherServlet.service(DispatcherServlet.java:67)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
> at
> org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
> at
> org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
> at
> org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
> at
> org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
> at
> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
> at org.mortbay.jetty.Server.handle(Server.java:326)
> at
> org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
> at
> org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:943)
> at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
> at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
> at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
> at
> org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
> at
> org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
> </pre>
> <hr /><i><small>Powered by Jetty://</small></i><br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
> <br/>
>
> </body>
> </html>
>
>
> RelFinder Query:
>
> SELECT * WHERE {
> <http://dopma-ropma.rand.org/people/{Target Person 1}> ?pf1 ?middle .
> <http://dopma-ropma.rand.org/people/{Target Person 2}> ?ps1 ?os1 .
> ?os1 ?ps2 ?middle .
> FILTER (
> (?pf1 != <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> )
> && (?pf1 != <http://www.w3.org/2004/02/skos/core#subject> )
> && (?pf1 != <http://www.w3.org/2002/07/owl#sameAs> )
> && (?pf1 != <http://purl.org/dc/terms/subject> )
> && (?pf1 != <http://purl.org/dc/terms/dateCopyrighted> )
> && (?pf1 != <http://purl.org/dc/terms/title> )
> && (?pf1 != <http://dopma-ropma.rand.org/people/employeeID2> )
> && (?pf1 != <http://xmlns.com/foaf/0.1/mbox> )
> && (?ps1 != <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> )
> && (?ps1 != <http://www.w3.org/2004/02/skos/core#subject> )
> && (?ps1 != <http://www.w3.org/2002/07/owl#sameAs> )
> && (?ps1 != <http://purl.org/dc/terms/subject> )
> && (?ps1 != <http://purl.org/dc/terms/dateCopyrighted> )
> && (?ps1 != <http://purl.org/dc/terms/title> )
> && (?ps1 != <http://dopma-ropma.rand.org/people/employeeID2> )
> && (?ps1 != <http://xmlns.com/foaf/0.1/mbox> )
> && (?ps2 != <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> )
> && (?ps2 != <http://www.w3.org/2004/02/skos/core#subject> )
> && (?ps2 != <http://www.w3.org/2002/07/owl#sameAs> )
> && (?ps2 != <http://purl.org/dc/terms/subject> )
> && (?ps2 != <http://purl.org/dc/terms/dateCopyrighted> )
> && (?ps2 != <http://purl.org/dc/terms/title> )
> && (?ps2 != <http://dopma-ropma.rand.org/people/employeeID2> )
> && (?ps2 != <http://xmlns.com/foaf/0.1/mbox> )
> && (!isLiteral(?middle))
> && (?middle != <http://dopma-ropma.rand.org/people/{Target Person 1}> )
> && (?middle != <http://dopma-ropma.rand.org/people/{Target Person 2}> )
> && (?middle != ?os1 ) && (!isLiteral(?os1))
> && (?os1 != <http://dopma-ropma.rand.org/people/{Target Person 1}> )
> && (?os1 != <http://dopma-ropma.rand.org/people/{Target Person 2}> )
> && (?os1 != ?middle ) ).
> } LIMIT 10
>
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--
| Rupert Westenthaler rupert.westentha...@gmail.com
| Bodenlehenstraße 11 ++43-699-11108907
| A-5500 Bischofshofen
