According to [1] the default RDF accept header in 3.1.0 and 3.1.1 is text/turtle,application/n-triples;q=0.9,application/rdf+xml;q=0.7, application/trig,application/n-quads;q=0.9,text/x-nquads;q=0.8,application/x-trig;q=0.7,application/ld+json;q=0.6, */*;q=0.5
that means Turtle is always the preferred format for SPARQL CONSTRUCT, DESCRIBE and also for Linked Data Dereferencing which is the current task. [1] https://github.com/apache/jena/blob/master/jena-arq/src/main/java/org/apache/jena/riot/WebContent.java#L184-L187 > I trusted so much Jena that I took for granted that no regression would > happen, but no software is without regression, and testing error catching > is of course the last thing people do, if ever ! > > So for my release of semantic_forms , I'll simply revert to 3.1.0 , with > priority to RDF/XML when reading, as Andy suggested in his code snippet. > > Ideally, the Accept: HTTP header should ask for: > > 1. N-triples > 2. RDF/XML > 3. JSON-LD > 4. Turtle > > or maybe swap 2 and 3 ? > > I don't know what Jena does currently. > > > 2017-01-20 9:50 GMT+01:00 Lorenz B. <[email protected]>: > >> Ah sorry, right. I tried it with version 3.1.0. >> >> I don't know which changes in the code lead to the different behavior. >> Especially not that you get 0 triples in 3.1.1 which looks more like no >> triple has to be parsed at all >> >>> Haaa, I got it ! >>> jena-3.1.0 brings the exception, jena-3.1.1 does not . >>> >>> cd ~/apps/apache-jena-3.1.0 ; JENA= ; for f in lib/*; do JENA=$JENA:$f; >>> done ; javac -cp $JENA ReadMgr.java ; java -cp $JENA ReadMgr >>> log4j:WARN No appenders could be found for logger (Jena). >>> log4j:WARN Please initialize the log4j system properly. >>> log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for >>> more info. >>> *org.apache.jena.riot.RiotException: [line: 1863, col: 13] Failed to >> find a >>> prefix name or keyword: –(8211;0x2013)* >>> >>> >>> 2017-01-20 9:18 GMT+01:00 Jean-Marc Vanel <[email protected]>: >>> >>>> 2017-01-19 22:26 GMT+01:00 Andy Seaborne <[email protected]>: >>>> >>>>> I get the parse error message with that code. >>>>> >>>> This is strange. I can't think of a reason for this difference in >>>> execution. My impression is that the exceptions worked some weeks or a >> few >>>> months ago. And what has changed since is the Ubuntu OS updates. >>>> >>>> I tried both these Java JDK: >>>> >>>> $ java -version >>>> openjdk version "1.8.0_111" >>>> OpenJDK Runtime Environment (build 1.8.0_111-8u111-b14-2ubuntu0.1 >>>> 6.10.2-b14) >>>> OpenJDK 64-Bit Server VM (build 25.111-b14, mixed mode) >>>> >>>> java -version >>>> java version "1.8.0_121" >>>> Java(TM) SE Runtime Environment (build 1.8.0_121-b13) >>>> Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode) >>>> >>>> My OS is >>>> uname -a >>>> Linux jmv-SMBIOSation 4.8.0-34-generic #36-Ubuntu SMP Wed Dec 21 >> 17:24:18 >>>> UTC 2016 x86_64 x86_64 x86_64 GNU/Linux >>>> >>>> >>>> Instead of working in a Scala eclipse environment, I downloaded a fresh >>>> Jena 3.1.1, and tried again: SAME THING ! >>>> >>>> cd ~/apps/apache-jena-3.1.1 >>>> for f in lib/*; do JENA=$JENA:$f; done >>>> javac -cp $JENA ReadMgr.java >>>> java -cp $JENA ReadMgr >>>> log4j:WARN No appenders could be found for logger (Jena). >>>> log4j:WARN Please initialize the log4j system properly. >>>> log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig >> for >>>> more info. >>>> *size 0* >>>> >>>> You can force the use of, say RDF/XML, by opening the connection >> directly >>>>> with HttpOp. You then have to tell the parse the syntax and base URI: >>>>> >>>> This I will do systematically, because as you explained , Turtle is >>>> fragile. But of course, I must understand why the exception does not >> occur, >>>> and the reading also does not occur. >>>> >>>> >>>> >>>>> try { >>>>> Graph g = GraphFactory.createDefaultGraph(); >>>>> String uri = "http://dbpedia.org/resource/Rome";; >>>>> try ( TypedInputStream in = HttpOp.execHttpGet(uri, >>>>> "application/rdf+xml") ) { >>>>> RDFDataMgr.read(g, in, uri, Lang.RDFXML); >>>>> } >>>>> System.out.println("size " + g.size()); >>>>> } catch (Throwable e) { >>>>> System.err.println(e); >>>>> } >>>>> >>>>> ==> >>>>> >>>>> size 8142 >>>>> >>>>> Andy >>>>> >>>>> >>>>> On 19/01/17 16:52, Jean-Marc Vanel wrote: >>>>> >>>>>> import org.apache.jena.graph.Graph; >>>>>> import org.apache.jena.riot.RDFDataMgr; >>>>>> >>>>>> public class ReadMgr { >>>>>> public static void main(String[] args) { >>>>>> try { >>>>>> Graph g = RDFDataMgr.loadGraph("http://d >>>>>> bpedia.org/resource/Rome >>>>>> "); >>>>>> System.out.println("size " + g.size()); >>>>>> } catch (Throwable e) { >>>>>> System.err.println(e); >>>>>> } >>>>>> } >>>>>> } >>>>>> >>>> -- >>>> Jean-Marc Vanel >>>> Profil: http://163.172.179.125:9111/display?displayuri=http%3A%2F%2F >>>> jmvanel.free.fr%2Fjmv.rdf%23me >>>> Déductions SARL - Consulting, services, training, >>>> Rule-based programming, Semantic Web >>>> +33 (0)6 89 16 29 52 <+33%206%2089%2016%2029%2052> >>>> Twitter: @jmvanel , @jmvanel_fr ; chat: irc://irc.freenode.net#eulergui >>>> >>> >> -- >> Lorenz Bühmann >> AKSW group, University of Leipzig >> Group: http://aksw.org - semantic web research center >> >> > -- Lorenz Bühmann AKSW group, University of Leipzig Group: http://aksw.org - semantic web research center
