Java Code Examples for org.openrdf.rio.RDFWriter#startRDF()

private void writeOutput( RDFWriter writer, Iterable<Statement> graph )
    throws RDFHandlerException
{
    writer.startRDF();
    writer.handleNamespace( "polygene", PolygeneRdf.POLYGENE_MODEL );
    writer.handleNamespace( "rdf", Rdfs.RDF );
    writer.handleNamespace( "rdfs", Rdfs.RDFS );
    for( Statement st : graph )
    {
        writer.handleStatement( st );
    }
    writer.endRDF();
}
 

/**
 * Converts a statement iterator to an input stream with serialized RDF data.
 * 
 * @param statements The statement iterator.
 * @param format The RDF format to use for serialization.
 * @return The serialized RDF data.
 * @throws RDFHandlerException in case of operation failure. 
 */
public static InputStream statementIteratorToRdfStream(final Iterator<Statement> statements, final RDFFormat format) throws RDFHandlerException {
	ByteArrayOutputStream stream = new ByteArrayOutputStream();
	RDFWriter rdfWriter = Rio.createWriter(format, stream);

	rdfWriter.startRDF();

	while (statements.hasNext()) {
		rdfWriter.handleStatement(statements.next());
	}

	rdfWriter.endRDF();
	return new ByteArrayInputStream(stream.toByteArray());
}
 

/**
 * Serialize an iteration of statements into a byte[] to send across the
 * wire.
 */
protected static byte[] serialize(final Iterable<? extends Statement> stmts,
        final RDFFormat format) throws Exception {
    
    final RDFWriterFactory writerFactory = 
        RDFWriterRegistry.getInstance().get(format);

    final ByteArrayOutputStream baos = new ByteArrayOutputStream();
    
    final RDFWriter writer = writerFactory.getWriter(baos);
    
    writer.startRDF();
    
    for (Statement stmt : stmts) {
    
        writer.handleStatement(stmt);
        
    }

    writer.endRDF();
    
    final byte[] data = baos.toByteArray();
    
    return data;

}
 

/**
     * Exports all told statements associated with the last commit point for the
     * KB.
     * 
     * @throws IOException
     * @throws SailException
     * @throws RDFHandlerException
     */
    public void exportData() throws IOException, SailException,
            RDFHandlerException {
        prepare();
//        final BigdataSail sail = new BigdataSail(kb);
//        try {
//            sail.initialize();
//            final SailConnection conn = sail.getReadOnlyConnection();
//            try {
                final CloseableIteration<? extends Statement, SailException> itr = conn
                        .getStatements(null/* s */, null/* p */, null/* o */,
                                includeInferred, new Resource[] {}/* contexts */);
                try {
                    final File file = new File(kbdir, "data."
                            + format.getDefaultFileExtension()+".gz");
                    System.out.println("Writing " + file);
                    final OutputStream os = new GZIPOutputStream(
                            new FileOutputStream(file));
                    try {
                        final RDFWriter writer = RDFWriterRegistry
                                .getInstance().get(format).getWriter(os);
                        writer.startRDF();
                        while (itr.hasNext()) {
                            final Statement stmt = itr.next();
                            writer.handleStatement(stmt);
                        }
                        writer.endRDF();
                    } finally {
                        os.close();
                    }
                } finally {
                    itr.close();
                }
//            } finally {
//                conn.close();
//            }
//        } finally {
//            sail.shutDown();
//        }

    }
 

@Override
public Void call() throws Exception {

  BigdataSailRepositoryConnection conn = null;
  
  try {

      conn = getQueryConnection();

      String mimeType = null;
      RDFFormat format = null;
      if (mimeTypes!=null) {
          mimeTypesLoop:
      	while(mimeTypes.hasMoreElements()) {
          	for (String mt:mimeTypes.nextElement().split(",")) {
          		mt = mt.trim();
               RDFFormat fmt = RDFWriterRegistry.getInstance()
                   .getFileFormatForMIMEType(mt);
               if (conn.getTripleStore().isQuads() && (mt.equals(RDFFormat.NQUADS.getDefaultMIMEType()) || mt.equals(RDFFormat.TURTLE.getDefaultMIMEType())) || !conn.getTripleStore().isQuads() && fmt != null) {
                   mimeType = mt;
                   format = fmt;
                   break mimeTypesLoop;
               }
          	}
          }
      }
      if (format==null) {
          if(conn.getTripleStore().isQuads()){
              mimeType = RDFFormat.NQUADS.getDefaultMIMEType();
          } else {
              mimeType = RDFFormat.NTRIPLES.getDefaultMIMEType();
          }
          format = RDFWriterRegistry.getInstance()
              .getFileFormatForMIMEType(mimeType);
      }
      resp.setContentType(mimeType);

      final OutputStream os = resp.getOutputStream();

      final RDFWriter w = RDFWriterRegistry.getInstance().get(format)
          .getWriter(os);

      RepositoryResult<Statement> stmts = null;

      try {
          w.startRDF();
          stmts = conn.getStatements(s, p, o, includeInferred, c);
          while(stmts.hasNext()){
              w.handleStatement(stmts.next());
          }
          w.endRDF();
      } finally {
          if (stmts != null) {
              stmts.close();
          }
          os.flush();
          os.close();
      }

      return null;
  } finally {
      if (conn != null) {
          conn.close();
      }
  }
}
 

/**
     * Send an RDF Graph as a response using content negotiation.
     * 
     * @param req
     * @param resp
     */
    static public void sendGraph(final HttpServletRequest req,
            final HttpServletResponse resp, final Graph g) throws IOException {
        /*
         * CONNEG for the MIME type.
         */
        final List<String> acceptHeaders = Collections.list(req.getHeaders("Accept"));
		final String acceptStr = ConnegUtil.getMimeTypeForQueryParameterQueryRequest(req
				.getParameter(BigdataRDFServlet.OUTPUT_FORMAT_QUERY_PARAMETER),
				acceptHeaders.toArray(new String[acceptHeaders.size()])); 
		
        final ConnegUtil util = new ConnegUtil(acceptStr);

        // The best RDFFormat for that Accept header.
        RDFFormat format = util.getRDFFormat();

        if (format == null)
            format = RDFFormat.RDFXML;

		RDFWriterFactory writerFactory = RDFWriterRegistry.getInstance().get(
				format);

		if (writerFactory == null) {

			if (log.isDebugEnabled()) {
				log.debug("No writer for format: format=" + format
						+ ", Accept=\"" + acceptStr + "\"");
			}

			format = RDFFormat.RDFXML;
			
			writerFactory = RDFWriterRegistry.getInstance().get(format);
			
		}

//        if (writerFactory == null) {
//
//			buildResponse(resp, HTTP_BADREQUEST, MIME_TEXT_PLAIN,
//					"No writer for format: Accept=\"" + acceptStr
//							+ "\", format=" + format);
//			
//			return;
//
//		}
		
        resp.setStatus(HTTP_OK);

        resp.setContentType(format.getDefaultMIMEType());

        final OutputStream os = resp.getOutputStream();
        try {
            final RDFWriter writer = writerFactory.getWriter(os);
            writer.startRDF();
            final Iterator<Statement> itr = g.iterator();
            while (itr.hasNext()) {
                final Statement stmt = itr.next();
                writer.handleStatement(stmt);
            }
            writer.endRDF();
            os.flush();
        } catch (RDFHandlerException e) {
        	// wrap and rethrow. will be handled by launderThrowable().
            throw new IOException(e);
        } finally {
            os.close();
        }
    }
 

/**
 * @param args
 */
public static void main(String[] args) {
	boolean[] inference = {false, true};
	long[] seeds = {1,2,3,4,5,6,7,8,9,10};
	double fraction = 0.05;
	int minSize = 0;
	int maxClasses = 3;
	int depth = 3;
	
	///*
	String saveDir = "datasets/BGS_small/BGSsubset";
	String loadDir = BGS_FOLDER;
	RDFFormat format = RDFFormat.NTRIPLES;
	//*/

	/*
	String saveDir = "datasets/AMsubset";
	String loadDir = AM_FOLDER;
	RDFFormat format = RDFFormat.TURTLE;
	//*/

	
	RDFDataSet tripleStore = new RDFFileDataSet(loadDir, format);

	LargeClassificationDataSet ds = new BGSDataSet(tripleStore, "http://data.bgs.ac.uk/ref/Lexicon/hasTheme", 10, 0.05, 5, 3);

	//LargeClassificationDataSet ds = new AMDataSet(tripleStore,  10, 0.05, 5, 3, true);

	
	for (long seed : seeds) {
		for (boolean inf : inference) {
			ds.createSubSet(seed, fraction, minSize, maxClasses);

			System.out.println("Getting Statements...");
			Set<Statement> stmts = RDFUtils.getStatements4Depth(tripleStore, ds.getRDFData().getInstances(), depth, inf);
			System.out.println("# Statements: " + stmts.size());
			stmts.removeAll(new HashSet<Statement>(ds.getRDFData().getBlackList()));
			System.out.println("# Statements: " + stmts.size() + ", after blackList");


			File dir = new File(saveDir + seed + inf);
			dir.mkdirs();

			File file = new File(saveDir + seed + inf, "subset.ttl");
			File instFile = new File(saveDir + seed + inf, "instances.txt");
			File targetFile = new File(saveDir + seed + inf, "target.txt");
			
			try {
				RDFWriter writer = Rio.createWriter(RDFFormat.TURTLE, new FileWriter(file));
				FileWriter instWriter = new FileWriter(instFile);
				FileWriter targetWriter = new FileWriter(targetFile);
				
				
				writer.startRDF();
				for (Statement stmt : stmts) {
					writer.handleStatement(stmt);
				}
				writer.endRDF();
				
				for (Resource inst : ds.getRDFData().getInstances()) {
					instWriter.write(inst.toString() + "\n");
				}
				instWriter.close();
				
				for (Double target : ds.getTarget()) {
					targetWriter.write(target.toString() + "\n");
				}
				targetWriter.close();

			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
	}
}
 

/**
 * Generates some statements and serializes them using the specified
 * {@link RDFFormat}.
 * 
 * @param ntriples
 *            The #of statements to generate.
 * @param format
 *            The format.
 * 
 * @return the serialized statements.
 */
protected byte[] genNTRIPLES(final int ntriples, final RDFFormat format)
        throws RDFHandlerException {

    final Graph g = genNTRIPLES2(ntriples);
    
    final RDFWriterFactory writerFactory = RDFWriterRegistry.getInstance()
            .get(format);

    if (writerFactory == null)
        fail("RDFWriterFactory not found: format=" + format);

    final ByteArrayOutputStream baos = new ByteArrayOutputStream();

    final RDFWriter writer = writerFactory.getWriter(baos);

    writer.startRDF();

    for (Statement stmt : g) {

        writer.handleStatement(stmt);

    }

    writer.endRDF();

    return baos.toByteArray();
    
}
 

/**
 * Write a graph on a buffer suitable for sending as an HTTP request body.
 * 
 * @param format
 *            The RDF Format to use.
 * @param g
 *            The graph.
 *            
 * @return The serialized data.
 * 
 * @throws RDFHandlerException
 */
static protected byte[] writeOnBuffer(final RDFFormat format, final Graph g)
        throws RDFHandlerException {

    final RDFWriterFactory writerFactory = RDFWriterRegistry.getInstance()
            .get(format);

    if (writerFactory == null)
        fail("RDFWriterFactory not found: format=" + format);

    final ByteArrayOutputStream baos = new ByteArrayOutputStream();

    final RDFWriter writer = writerFactory.getWriter(baos);

    writer.startRDF();

    for (Statement stmt : g) {

        writer.handleStatement(stmt);

    }

    writer.endRDF();

    return baos.toByteArray();

}