Java Code Examples for org.openrdf.repository.RepositoryConnection#getStatements()

@Override
public void activate(final Collection<SesameSwitchSetMatch> matches) throws RepositoryException {
	final RepositoryConnection con = driver.getConnection();
	final ValueFactory vf = driver.getValueFactory();

	final URI currentPositionProperty = vf.createURI(BASE_PREFIX + CURRENTPOSITION);

	for (final SesameSwitchSetMatch match : matches) {
		final Resource sw = match.getSw();
		final Value position = match.getPosition();
		final Value currentPosition = match.getCurrentPosition();

		final RepositoryResult<Statement> statementsToRemove = con.getStatements(sw, currentPositionProperty, currentPosition, false);
		while (statementsToRemove.hasNext()) {
			con.remove(statementsToRemove.next());
		}

		con.add(sw, currentPositionProperty, position);
	}
}
 

@Override
public void activate(final Collection<SesameConnectedSegmentsMatch> matches) throws RepositoryException {
	final RepositoryConnection con = driver.getConnection();
	final ValueFactory vf = driver.getValueFactory();

	final URI connectsTo = vf.createURI(BASE_PREFIX + CONNECTS_TO);
	for (final SesameConnectedSegmentsMatch match : matches) {
		// delete segment2 by removing all (segment2, _, _) and (_, _, segment2) triples
		final RepositoryResult<Statement> outgoingEdges = con.getStatements(match.getSegment2(), null, null, true);
		while (outgoingEdges.hasNext()) {
			con.remove(outgoingEdges.next());
		}
		final RepositoryResult<Statement> incomingEdges = con.getStatements(null, null, match.getSegment2(), true);
		while (incomingEdges.hasNext()) {
			con.remove(incomingEdges.next());
		}

		// insert (segment1)-[:connectsTo]->(segment3) edge
		con.add(match.getSegment1(), connectsTo, match.getSegment3());
	}
}
 

@Override
public void activate(final Collection<SesamePosLengthMatch> matches) throws RepositoryException {
	final RepositoryConnection con = driver.getConnection();
	final ValueFactory vf = driver.getValueFactory();

	final URI lengthProperty = vf.createURI(BASE_PREFIX + LENGTH);

	for (final SesamePosLengthMatch match : matches) {
		final Resource segment = match.getSegment();
		final Value length = match.getLength();

		final RepositoryResult<Statement> statementsToRemove = con.getStatements(segment, lengthProperty, length, true);
		while (statementsToRemove.hasNext()) {
			final Statement oldStatement = statementsToRemove.next();
			con.remove(oldStatement);
		}

		final Integer lengthInteger = new Integer(length.stringValue());
		final Integer newLengthInteger = -lengthInteger + 1;
		final Literal newLength = vf.createLiteral(newLengthInteger);
		final Statement newStatement = vf.createStatement(segment, lengthProperty, newLength);
		con.add(newStatement);
	}
}
 

@Override
public void activate(final Collection<SesamePosLengthInjectMatch> matches) throws RepositoryException {
	final RepositoryConnection con = driver.getConnection();
	final ValueFactory vf = driver.getValueFactory();

	final URI typeURI = vf.createURI(BASE_PREFIX + ModelConstants.LENGTH);
	final Literal zeroLiteral = vf.createLiteral(0);

	for (final SesamePosLengthInjectMatch match : matches) {
		final URI segment = match.getSegment();

		final RepositoryResult<Statement> statementsToRemove = con.getStatements(segment, typeURI, null, true);
		con.remove(statementsToRemove);

		con.add(segment, typeURI, zeroLiteral);
	}
}
 

/**
 * Tuple pattern query - find all statements with the pattern, where null is
 * a wildcard
 * 
 * @param s
 *            subject (null for wildcard)
 * @param p
 *            predicate (null for wildcard)
 * @param o
 *            object (null for wildcard)
 * @param contexts
 *            varArgs contexts (use default graph if null)
 * @return serialized graph of results
 */
public List<Statement> tuplePattern(Resource s, URI p, Value o,
		Resource... contexts) {
	try {
		RepositoryConnection con = currentRepository.getConnection();
		try {
			RepositoryResult<Statement> repres = con.getStatements(s, p, o,
					true, contexts);
			ArrayList<Statement> reslist = new ArrayList<Statement>();
			while (repres.hasNext()) {
				reslist.add(repres.next());
			}
			return reslist;
		} finally {
			con.close();
		}
	} catch (Exception e) {
		e.printStackTrace();
	}
	return null;
}
 

private int getSize(Repository repository) throws RepositoryException {
	int size = 0;
	RepositoryConnection connection = null;
	RepositoryResult<Statement> iter = null;
	try {
		connection = repository.getConnection();
		iter = connection.getStatements(null, null, null, false);
		while (iter.hasNext()) {
			iter.next();
			++size;
		}
	} finally {
		if (iter != null)
			iter.close();
		if (connection != null)
			connection.close();
	}
	return size;
}
 

private void importRepository(RepositoryConnection connection, TripleSink sink) throws RepositoryException {
	RepositoryResult<Statement> statements = null;
	try {
		statements=connection.getStatements(null, null, null, false);
		SesameModelParser tripleParser=new SesameModelParser(getNamespaces(connection));
		while(statements.hasNext()) {
			sink.addTriple(tripleParser.parseStatement(statements.next()));
		}
	} finally {
		closeQuietly(statements, "Could not close results after parsing statements");
	}
}
 

private void write(DataSource ds, RepositoryConnection conn, Resource context) throws RepositoryException {
    LOG.info("Writing context {}", context);

    RepositoryResult<Statement> statements = conn.getStatements(null, null, null, true, context);
    Model model = new LinkedHashModel();
    QueryResults.addAll(statements, model);
    copyNamespacesToModel(conn, model);

    String outname = context.toString();
    write(model, outputStream(ds, outname));
}
 

@Override
public List<Statement> getStatements(Resource subject, URI predicate, Value object, boolean allowInference) {
	List<Statement> resGraph = new ArrayList<Statement>();

	try {
		RepositoryConnection repCon = rdfRep.getConnection();

		try {
			
			
			RepositoryResult<Statement> statements = repCon.getStatements(subject, predicate, object, allowInference);

			try {
				while (statements.hasNext()) {
					resGraph.add(statements.next());
				}
			}
			finally {
				statements.close();
			}
		} finally {
			repCon.close();
		}

	} catch (Exception e) {
		e.printStackTrace();
	}

	return resGraph;		
}
 

public static void readSomeData(Repository repo) throws Exception {

		RepositoryConnection cxn = repo.getConnection();
		int counter = 0;
		try {

			RepositoryResult<Statement> stmts = cxn.getStatements(null, null, null, true /*
																						* include
																						* inferred
																						*/);
			while (stmts.hasNext()) {
				Statement stmt = stmts.next();
				Resource s = stmt.getSubject();
				URI p = stmt.getPredicate();
				Value o = stmt.getObject();
				// do something with the statement
				LOG.info(stmt);

				// cast to BigdataStatement to get at additional information
				BigdataStatement bdStmt = (BigdataStatement) stmt;
				if (bdStmt.isExplicit()) {
					// do one thing
				} else if (bdStmt.isInferred()) {
					// do another thing
				} else { // bdStmt.isAxiom()
					// do something else
				}
				LOG.info(bdStmt.getStatementType());
				counter++;
			}

		} finally {
			// close the repository connection
			cxn.close();

			LOG.info("Number of Triples: " + counter);
		}

	}
 

private void executeTest(final SailRepository repo)
		throws RepositoryException, MalformedQueryException,
		QueryEvaluationException, RDFParseException, RDFHandlerException,
		IOException {
	try {
		repo.initialize();
		final RepositoryConnection conn = repo.getConnection();
		try {
			conn.setAutoCommit(false);
			final ValueFactory vf = conn.getValueFactory();
	        final URI uri = vf.createURI("os:/elem/example");
	        // run a query which looks for a statement and then adds it if it is not found.
	        addDuringQueryExec(conn, uri, RDF.TYPE, vf.createURI("os:class/Clazz"));
	        // now try to export the statements.
        	final RepositoryResult<Statement> stats = conn.getStatements(null, null, null, false);
	        try {
	        	// materialize the newly added statement.
	        	stats.next();
	        } catch (RuntimeException e) {
	        	fail(e.getLocalizedMessage(), e); // With Bigdata this fails
	        } finally {
	        	stats.close();
	        }
	        conn.rollback(); // discard the result (or commit, but do something to avoid a logged warning from Sesame).
		} finally {
			conn.close();
		}
	} finally {
		repo.shutDown();
	}
}
 

private Collection<Statement> getStatementsForContext(final RepositoryConnection conn,
        final URI context) throws RepositoryException {
    RepositoryResult<Statement> res = null;
    final Collection<Statement> statements = new ArrayList<Statement>();
    try {
        res = conn.getStatements(null, null, null, false, context);
        while (res.hasNext()) {
            statements.add(res.next());
        }
    } finally {
        res.close();
    }
    return statements;
}
 

private void executeTest(final SailRepository repo)
		throws RepositoryException, MalformedQueryException,
		QueryEvaluationException, RDFParseException, RDFHandlerException,
		IOException {
	try {
		repo.initialize();
		final RepositoryConnection conn = repo.getConnection();
		try {
			conn.setAutoCommit(false);
			final ValueFactory vf = conn.getValueFactory();
	        final URI uri = vf.createURI("os:/elem/example");
	        // run a query which looks for a statement and then adds it if it is not found.
	        addDuringQueryExec(conn, uri, RDF.TYPE, vf.createURI("os:class/Clazz"));
	        // now try to export the statements.
        	final RepositoryResult<Statement> stats = conn.getStatements(null, null, null, false);
	        try {
	        	// materialize the newly added statement.
	        	stats.next();
	        } catch (RuntimeException e) {
	        	fail(e.getLocalizedMessage(), e); // With Bigdata this fails
	        } finally {
	        	stats.close();
	        }
	        conn.rollback(); // discard the result (or commit, but do something to avoid a logged warning from Sesame).
		} finally {
			conn.close();
		}
	} finally {
		repo.shutDown();
	}
}
 

/**
 * Returns all statements that are present in any context of a repository having the specified subject, predicate and/or object.
 * @param connection A connection to the repository to query.
 * @param subject The subject the returned triples should have or null for any subject.
 * @param predicate The predicate the returned triples should have or null for any predicate.
 * @param object The object the returned triples should have or null for any object.
 * @return Returns the set of all triples present in the repository having the desired spo-structure.
 * @throws RepositoryException Thrown if an error occurs while querying the repository.
 */
private Collection<Statement> getStatements(RepositoryConnection connection, Resource subject, URI predicate, Value object) throws RepositoryException {
    // Query the repository:
    RepositoryResult<Statement> result = connection.getStatements(subject, predicate, object, false);

    // Fetch all statements from the result:
    Collection<Statement> statements = new HashSet<>();
    while (result.hasNext()) {
        statements.add(result.next());
    }
    return statements;
}
 

@Override
public void activate(final Collection<SesameSwitchSetInjectMatch> matches) throws RepositoryException {
	final RepositoryConnection con = driver.getConnection();
	final ValueFactory vf = driver.getValueFactory();

	final URI currentPositionProperty = vf.createURI(BASE_PREFIX + CURRENTPOSITION);

	for (final SesameSwitchSetInjectMatch match : matches) {
		final URI sw = match.getSw();
		final RepositoryResult<Statement> statements = con.getStatements(sw, currentPositionProperty, null, true);
		if (!statements.hasNext()) {
			continue;
		}

		final Statement oldStatement = statements.next();

		// delete old statement
		con.remove(oldStatement);

		// get next enum value
		final URI currentPositionURI = (URI) oldStatement.getObject();
		final String currentPositionRDFString = currentPositionURI.getLocalName();
		final String currentPositionString = RdfHelper.removePrefix(Position.class, currentPositionRDFString);
		final Position currentPosition = Position.valueOf(currentPositionString);
		final Position newCurrentPosition = Position.values()[(currentPosition.ordinal() + 1) % Position.values().length];
		final String newCurrentPositionString = RdfHelper.addEnumPrefix(newCurrentPosition);
		final URI newCurrentPositionUri = vf.createURI(BASE_PREFIX + newCurrentPositionString);

		// set new value
		con.add(sw, currentPositionProperty, newCurrentPositionUri);
	}
}
 

private static int statementsCount(RepositoryConnection conn, Resource ctx) {
    int counter = 0;
    try {
        RepositoryResult<Statement> statements = conn.getStatements(null, null, null, true, ctx);
        while (statements.hasNext()) {
            counter++;
            statements.next();
        }
    } catch (RepositoryException e) {
        LOG.error(e.getMessage());
    }
    return counter;
}
 

@Override
public void print(PrintStream out) {
    out.println("TripleStore based on Blazegraph");
    RepositoryConnection conn;
    try {
        conn = repo.getConnection();
        try {
            RepositoryResult<Resource> ctxs = conn.getContextIDs();
            while (ctxs.hasNext()) {
                Resource ctx = ctxs.next();
                int size = statementsCount(conn, ctx);
                out.println("    " + ctx + " : " + size);
                if (PRINT_ALL_STATEMENTS) {
                    RepositoryResult<Statement> statements = conn.getStatements(null, null, null, true, ctx);
                    while (statements.hasNext()) {
                        Statement statement = statements.next();
                        out.println("        " + statement.getSubject() + " " + statement.getPredicate() + " "
                            + statement.getObject());
                    }
                }
            }
        } finally {
            closeConnection(conn, "Printing");
        }
    } catch (RepositoryException e) {
        LOG.error(e.getMessage());
    }
}
 

/**
 * Read some statements from a repository.
 * 
 * @param repo
 * @param uri
 * @throws Exception
 */
public void readSomeData(Repository repo, URI uri) throws Exception {
    
    /*
     * With MVCC, you read from a historical state to avoid blocking and
     * being blocked by writers.  BigdataSailRepository.getQueryConnection
     * gives you a view of the repository at the last commit point.
     */
    RepositoryConnection cxn;
    if (repo instanceof BigdataSailRepository) { 
        cxn = ((BigdataSailRepository) repo).getReadOnlyConnection();
    } else {
        cxn = repo.getConnection();
    }
    
    try {
        
        RepositoryResult<Statement> stmts = 
            cxn.getStatements(uri, null, null, true /* include inferred */);
        while (stmts.hasNext()) {
            Statement stmt = stmts.next();
            Resource s = stmt.getSubject();
            URI p = stmt.getPredicate();
            Value o = stmt.getObject();
            // do something with the statement
            log.info(stmt);
            
            // cast to BigdataStatement to get at additional information
            BigdataStatement bdStmt = (BigdataStatement) stmt;
            if (bdStmt.isExplicit()) {
                // do one thing
            } else if (bdStmt.isInferred()) {
                // do another thing
            } else { // bdStmt.isAxiom()
                // do something else
            }
            log.info(bdStmt.getStatementType());
        }
        
    } finally {
        // close the repository connection
        cxn.close();
    }
    
}