SPARSQL Update Error.

Question

What's wrong with this code? which model could be created?

public boolean execUpdate(String _sparsql){

boolean ret = false;

_sparsql = "PREFIX dc: <http://purl.org/dc/elements/1.1/>"+

     " INSERT DATA"+

     "{<http://example/book8> dc:title    \"A new book8\" ;"+

     "                        dc:creator  \"A.N.Other8\" .}";

InputStream in  =  new FileInputStream("c:\\books.ttl");

Model model = ModelFactory.createDefaultModel();

UpdateRequest request = UpdateFactory.create();

try {

  request.add(sparsql);

  model.read(in,null,"TURTLE");

  model.enterCriticalSection(Lock.WRITE);

  UpdateAction.execute(request, model);

  model.commit();

  model.leaveCriticalSection();

  System.out.println("==== finished ====");
  ret = true;
}catch (Exception e){         
} finally {   
}
return ret;
}

Error:result

[2555-12-15 21:16:10.468]  ERROR java.lang.Class - java.lang.UnsupportedOperationException: this model does not support transactions
    at com.hp.hpl.jena.graph.impl.SimpleTransactionHandler.notSupported(SimpleTransactionHandler.java:45)
    at com.hp.hpl.jena.graph.impl.SimpleTransactionHandler.begin(SimpleTransactionHandler.java:34)
    at com.hp.hpl.jena.rdf.model.impl.ModelCom.begin(ModelCom.java:1268)
    at OntFile.OntFile.execUpdate(OntFile.java:163)
    at OntFile.OntFile.main(OntFile.java:240)

Answer 1

1

Memory models don't support transactions. Remove the model.commit.

This style is as safer although if an exception occurs in your code, the model is possible logically inconsistent from the applications POV anyway.

model.enterCriticalSection(Lock.WRITE);
try{ 
   ...
} finally { model.leaveCriticalSection(); }

link

answered 15 Dec '12, 12:45

AndyS ♦
9.6k●2●7
accept rate: 33%

Answer 2

0

Thank you for suggestion AndyS. Anyway the solution for write back below. :) ...

m.enterCriticalSection(Lock.WRITE);

UpdateAction.execute(request, m);

FileWriter fstream = new FileWriter("c:\books.ttl");

BufferedWriter out = new BufferedWriter(fstream);

String lang = FileUtils.guessLang("c:\books.ttl");

m.write(out,lang);

m.leaveCriticalSection();
...

link

answered 15 Dec '12, 13:18

Ton Rawat
26●2
accept rate: 50%

1

If you want atomic, safe update of a file on disk, then playing the "write a new file (in the same directory), delete the old file, move the new file to the old file" dance (with checks for a machine crash between rm and mv if you care), is the way to do it.

(15 Dec '12, 13:24) AndyS ♦

SPARSQL Update Error.

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