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From Benson Margulies <bimargul...@gmail.com>
Subject Re: Unexpected end of input errors on reading from dbpedia
Date Tue, 08 Feb 2011 15:23:57 GMT
Hmm. This works fine in CXF. Do you all care enough to put more effort
into avoiding the extra buffer?

On Tue, Feb 8, 2011 at 9:10 AM, Simon Wibberley
<simon.wibberley@sussex.ac.uk> wrote:
>> What version of woodstox?
>
> 3.2.9 and 4.1.1 I believe.
>
> Simon
>
>> On Tue, Feb 8, 2011 at 8:37 AM, Andy Seaborne
>> <andy.seaborne@epimorphics.com> wrote:
>>> Simon,
>>>
>>> Thanks for a complete, minimal example.  I get the same error.
>>>
>>> I suspect it's not woodstox per se, but a lower level networking issue
>>> because I can get things to work by reading the data as fast as possible.
>>>  Maybe woodstow's use of the inputstream is seeing the connection close flag
>>> without making sure there isn't more data to read.
>>>
>>> The code in ARQ SVN has a workaround for this - it slurps up the network
>>> bytes as fast as possible, then passes them to woodstox; woodstox is not
>>> then working over the network input stream but instead a
>>> ByteArrayInputStream.
>>>
>>> (An alternative, I tried was adding a buffering layer to the input stream
>>> but that didn't work).
>>>
>>>        Andy
>>>
>>> On 07/02/11 23:09, Simon Wibberley wrote:
>>>>
>>>> Hi there,
>>>>
>>>> I'm trying to query dbpedia for a list of company names. I'm
>>>> inconsistently getting WstxEOFException's caught by jena, which then
>>>> raises a ResultSetException. This happens after some data has been read
>>>> successfully. Following the tcp stream in wireshark shows a complete
>>>> response from the dbpedia server.
>>>>
>>>> Is this a bug in woodstox? I've tried replacing the libs with wstx4 and
>>>> stax2, but same error occurred. Is there anything I'm doing wrong/badly
>>>> with jena/sparql? (I'm relatively new to this). The minimal test case
>>>> below seems to reproduce the error (output also below) reliably. I've
>>>> tried this on both windows7 and OS X 10.6 from different locations.
>>>> Could you check to see if you get the same error?
>>>>
>>>> Any ideas?
>>>>
>>>> Many thanks,
>>>>
>>>> Simon Wibberley
>>>>
>>>> import com.hp.hpl.jena.query.Query;
>>>> import com.hp.hpl.jena.query.QueryExecution;
>>>> import com.hp.hpl.jena.query.QueryExecutionFactory;
>>>> import com.hp.hpl.jena.query.QueryFactory;
>>>> import com.hp.hpl.jena.query.QuerySolution;
>>>> import com.hp.hpl.jena.query.ResultSet;
>>>> import com.hp.hpl.jena.rdf.model.RDFNode;
>>>>
>>>> public class TestJena {
>>>> public static void main(String[] args) {
>>>>
>>>> String queryString = "PREFIX rdf:
>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"
>>>> + "PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>"
>>>> + "SELECT ?var "
>>>> + "WHERE { ?var rdf:type dbpedia-owl:Company . }";
>>>>
>>>> Query query = QueryFactory.create(queryString);
>>>>
>>>> QueryExecution qexec = QueryExecutionFactory.sparqlService(
>>>> "http://dbpedia.org/sparql", query);
>>>> ResultSet rs = null;
>>>>
>>>> rs = qexec.execSelect();
>>>> qexec.close();
>>>>
>>>> while(rs.hasNext()) {
>>>> QuerySolution sqs = rs.next();
>>>> RDFNode node = sqs.get("var");
>>>> System.out.println(node);
>>>> }
>>>> }
>>>>
>>>>
>>>> }
>>>>
>>>> com.ctc.wstx.exc.WstxEOFException: Unexpected EOF; was expecting a close
>>>> tag for element <uri>
>>>> at [row,col {unknown-source}]: [106,47]
>>>> at
>>>> com.ctc.wstx.sr.StreamScanner.throwUnexpectedEOF(StreamScanner.java:686)
>>>> at
>>>>
>>>> com.ctc.wstx.sr.BasicStreamReader.nextFromTree(BasicStreamReader.java:2730)
>>>> at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1019)
>>>> at
>>>>
>>>> com.ctc.wstx.sr.BasicStreamReader.getElementText(BasicStreamReader.java:669)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.getOneSolution(XMLInputStAX.java:480)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:216)
>>>>
>>>> at sw206.TestJena.main(TestJena.java:31)
>>>> Exception in thread "main"
>>>> com.hp.hpl.jena.sparql.resultset.ResultSetException: XMLStreamException:
>>>> Unexpected EOF; was expecting a close tag for element <uri>
>>>> at [row,col {unknown-source}]: [106,47]
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.staxError(XMLInputStAX.java:510)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:220)
>>>>
>>>> at sw206.TestJena.main(TestJena.java:31)
>>>> Caused by: com.ctc.wstx.exc.WstxEOFException: Unexpected EOF; was
>>>> expecting a close tag for element <uri>
>>>> at [row,col {unknown-source}]: [106,47]
>>>> at
>>>> com.ctc.wstx.sr.StreamScanner.throwUnexpectedEOF(StreamScanner.java:686)
>>>> at
>>>>
>>>> com.ctc.wstx.sr.BasicStreamReader.nextFromTree(BasicStreamReader.java:2730)
>>>> at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1019)
>>>> at
>>>>
>>>> com.ctc.wstx.sr.BasicStreamReader.getElementText(BasicStreamReader.java:669)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.getOneSolution(XMLInputStAX.java:480)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:216)
>>>>
>>>> ... 1 more
>>>> 22:59:25,250 WARN XMLInputStAX$ResultSetStAX:73 - StAX error:
>>>> XMLStreamException: Unexpected EOF; was expecting a close tag for
>>>> element <uri>
>>>> at [row,col {unknown-source}]: [106,47]
>>>> com.ctc.wstx.exc.WstxEOFException: Unexpected EOF; was expecting a close
>>>> tag for element <uri>
>>>> at [row,col {unknown-source}]: [106,47]
>>>> at
>>>> com.ctc.wstx.sr.StreamScanner.throwUnexpectedEOF(StreamScanner.java:686)
>>>> at
>>>>
>>>> com.ctc.wstx.sr.BasicStreamReader.nextFromTree(BasicStreamReader.java:2730)
>>>> at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1019)
>>>> at
>>>>
>>>> com.ctc.wstx.sr.BasicStreamReader.getElementText(BasicStreamReader.java:669)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.getOneSolution(XMLInputStAX.java:480)
>>>>
>>>> at
>>>>
>>>> com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:216)
>>>>
>>>> at sw206.TestJena.main(TestJena.java:31)
>>>>
>>>>
>>>>
>>>>
>>>
>
>
> --
> Simon Wibberley
> DPhil Student
>
> Machine Learning and Computational Linguistics
> Chichester 1, R203
> Informatics
> University of Sussex
> Brighton, UK
> simon.wibberley@sussex.ac.uk
>
>
>
>

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