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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 14:06:39 GMT
What version of woodstox?

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)
>>
>>
>>
>>
>

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