Java Code Examples for org.eclipse.rdf4j.rio.RDFHandler#handleStatement()

public void render(ParsedBooleanQuery query, RDFHandler handler) throws RDFHandlerException {
	handler.startRDF();
	Resource querySubj = valueFactory.createBNode();
	handler.handleStatement(valueFactory.createStatement(querySubj, RDF.TYPE, SP.ASK_CLASS));
	if (output.text) {
		handler.handleStatement(valueFactory.createStatement(querySubj, SP.TEXT_PROPERTY,
				valueFactory.createLiteral(query.getSourceString())));
	}
	if (output.rdf) {
		Resource whereBNode = valueFactory.createBNode();
		handler.handleStatement(valueFactory.createStatement(querySubj, SP.WHERE_PROPERTY, whereBNode));
		TupleExpr expr = query.getTupleExpr();
		SpinVisitor visitor = new AskVisitor(handler, whereBNode, query.getDataset());
		expr.visit(visitor);
		visitor.end();
	}
	handler.endRDF();
}
 

public void render(ParsedTupleQuery query, RDFHandler handler) throws RDFHandlerException {
	handler.startRDF();
	Resource querySubj = valueFactory.createBNode();
	handler.handleStatement(valueFactory.createStatement(querySubj, RDF.TYPE, SP.SELECT_CLASS));
	if (output.text) {
		handler.handleStatement(valueFactory.createStatement(querySubj, SP.TEXT_PROPERTY,
				valueFactory.createLiteral(query.getSourceString())));
	}
	if (output.rdf) {
		TupleExpr expr = query.getTupleExpr();
		SpinVisitor visitor = new SpinVisitor(handler, null, querySubj, query.getDataset());
		expr.visit(visitor);
		visitor.end();
	}
	handler.endRDF();
}
 

public void render(ParsedDescribeQuery query, RDFHandler handler) throws RDFHandlerException {
	handler.startRDF();
	Resource querySubj = valueFactory.createBNode();
	handler.handleStatement(valueFactory.createStatement(querySubj, RDF.TYPE, SP.DESCRIBE_CLASS));
	if (output.text) {
		handler.handleStatement(valueFactory.createStatement(querySubj, SP.TEXT_PROPERTY,
				valueFactory.createLiteral(query.getSourceString())));
	}
	if (output.rdf) {
		TupleExpr expr = query.getTupleExpr();
		SpinVisitor visitor = new DescribeVisitor(handler, querySubj, query.getDataset());
		expr.visit(visitor);
		visitor.end();
	}
	handler.endRDF();
}
 

public void render(ParsedGraphQuery query, RDFHandler handler) throws RDFHandlerException {
	handler.startRDF();
	Resource querySubj = valueFactory.createBNode();
	handler.handleStatement(valueFactory.createStatement(querySubj, RDF.TYPE, SP.CONSTRUCT_CLASS));
	if (output.text) {
		handler.handleStatement(valueFactory.createStatement(querySubj, SP.TEXT_PROPERTY,
				valueFactory.createLiteral(query.getSourceString())));
	}
	if (output.rdf) {
		TupleExpr expr = query.getTupleExpr();
		SpinVisitor visitor = new ConstructVisitor(handler, querySubj, query.getDataset());
		expr.visit(visitor);
		visitor.end();
	}
	handler.endRDF();
}
 

/**
 * Reports a graph query result to an {@link RDFHandler}. <br>
 * The {@link GraphQueryResult#close()} method will always be called before this method returns.<br>
 * If there is an exception generated by the GraphQueryResult, {@link RDFHandler#endRDF()} will not be called.
 *
 * @param gqr        The query result to report.
 * @param rdfHandler The handler to report the query result to.
 * @throws RDFHandlerException      If such an exception is thrown by the used RDF writer.
 * @throws QueryEvaluationException
 */
public static void report(GraphQueryResult gqr, RDFHandler rdfHandler)
		throws RDFHandlerException, QueryEvaluationException {
	try {
		rdfHandler.startRDF();

		for (Map.Entry<String, String> entry : gqr.getNamespaces().entrySet()) {
			String prefix = entry.getKey();
			String namespace = entry.getValue();
			rdfHandler.handleNamespace(prefix, namespace);
		}

		while (gqr.hasNext()) {
			Statement st = gqr.next();
			rdfHandler.handleStatement(st);
		}
	} finally {
		gqr.close();
	}
	rdfHandler.endRDF();
}
 

@Override
public void exportStatements(Resource subj, IRI pred, Value obj, boolean includeInferred, RDFHandler handler,
		Resource... contexts) throws RepositoryException, RDFHandlerException {
	handler.startRDF();

	try ( // Export namespace information
			CloseableIteration<? extends Namespace, RepositoryException> nsIter = getNamespaces()) {
		while (nsIter.hasNext()) {
			Namespace ns = nsIter.next();
			handler.handleNamespace(ns.getPrefix(), ns.getName());
		}
	}

	// Export statements

	try (CloseableIteration<? extends Statement, RepositoryException> stIter = getStatements(subj, pred, obj,
			includeInferred, contexts)) {
		while (stIter.hasNext()) {
			handler.handleStatement(stIter.next());
		}
	}

	handler.endRDF();
}
 

/**
 * Exports all statements contained in the supplied statement iterator and all relevant namespace information to the
 * supplied RDFHandler.
 */
protected void exportStatements(RepositoryResult<Statement> stIter, RDFHandler handler)
		throws RepositoryException, RDFHandlerException {
	try {
		handler.startRDF();
		try ( // Export namespace information
				RepositoryResult<Namespace> nsIter = getNamespaces()) {
			while (nsIter.hasNext()) {
				Namespace ns = nsIter.next();
				handler.handleNamespace(ns.getPrefix(), ns.getName());
			}
		}
		// Export statemnts
		while (stIter.hasNext()) {
			handler.handleStatement(stIter.next());
		}
		handler.endRDF();
	} finally {
		stIter.close();
	}
}
 

/**
 * Writes the given statements to the given {@link RDFHandler}.
 * <p>
 * If the collection is a {@link Model}, its namespaces will also be written.
 *
 * @param iterable A collection of statements, such as a {@link Model}, to be written.
 */
public static void write(Iterable<Statement> iterable, RDFHandler writer, SesameTransformer transformer,
                         StatementHandler... statementHandlers) {
    writer.startRDF();

    if (iterable instanceof Model) {
        for (Namespace nextNamespace : ((Model) iterable).getNamespaces()) {
            writer.handleNamespace(nextNamespace.getPrefix(), nextNamespace.getName());
        }
    }

    for (final Statement st : iterable) {
        Statement handledStatement = st;
        for (StatementHandler statementHandler : statementHandlers) {
            handledStatement = statementHandler.handleStatement(handledStatement);
        }
        org.eclipse.rdf4j.model.Statement sesameStatement = transformer.sesameStatement(handledStatement);
        writer.handleStatement(sesameStatement);
    }
    writer.endRDF();
}
 

/**
 * Handles all results of a query. Closes the query iterator when done.
 * @param subject the subject {@link Resource} to query for.
 * @param predicate the predicate {@link IRI} to query for.
 * @param object the object {@link Value} to query for.
 * @param rdfStatementHandler the {@link RDFHandler} to use for handling
 * each statement returned. (not {@code null})
 * @param contexts the context {@link Resource}s to query for.
 * @throws QueryEvaluationException
 */
public void queryAll(final Resource subject, final IRI predicate, final Value object, final RDFHandler rdfStatementHandler, final Resource... contexts) throws QueryEvaluationException {
    checkNotNull(rdfStatementHandler);
    final CloseableIteration<Statement, QueryEvaluationException> iter = RyaDAOHelper.query(ryaDao, subject, predicate, object, conf, contexts);
    try {
        while (iter.hasNext()) {
            final Statement statement = iter.next();
            try {
                rdfStatementHandler.handleStatement(statement);
            } catch (final Exception e) {
                throw new QueryEvaluationException("Error handling statement.", e);
            }
        }
    } finally {
        if (iter != null) {
            iter.close();
        }
    }
}
 

/**
 * Handles only the first result of a query. Closes the query iterator when
 * done.
 * @param subject the subject {@link Resource} to query for.
 * @param predicate the predicate {@link IRI} to query for.
 * @param object the object {@link Value} to query for.
 * @param rdfStatementHandler the {@link RDFHandler} to use for handling the
 * first statement returned. (not {@code null})
 * @param contexts the context {@link Resource}s to query for.
 * @throws QueryEvaluationException
 */
public void queryFirst(final Resource subject, final IRI predicate, final Value object, final RDFHandler rdfStatementHandler, final Resource... contexts) throws QueryEvaluationException {
    checkNotNull(rdfStatementHandler);
    final CloseableIteration<Statement, QueryEvaluationException> iter = RyaDAOHelper.query(ryaDao, subject, predicate, object, conf, contexts);
    try {
        if (iter.hasNext()) {
            final Statement statement = iter.next();
            try {
                rdfStatementHandler.handleStatement(statement);
            } catch (final Exception e) {
                throw new QueryEvaluationException("Error handling statement.", e);
            }
        }
    } finally {
        if (iter != null) {
            iter.close();
        }
    }
}
 

public void render(ParsedUpdate update, RDFHandler handler) throws RDFHandlerException {
	handler.startRDF();

	for (Map.Entry<String, String> entry : update.getNamespaces().entrySet()) {
		handler.handleNamespace(entry.getKey(), entry.getValue());
	}

	String[] sourceStrings = update.getSourceString().split("\\s*;\\s*");
	List<UpdateExpr> updateExprs = update.getUpdateExprs();
	Map<UpdateExpr, Dataset> datasets = update.getDatasetMapping();
	for (int i = 0; i < updateExprs.size(); i++) {
		UpdateExpr updateExpr = updateExprs.get(i);
		Resource updateSubj = valueFactory.createBNode();
		Dataset dataset = datasets.get(updateExpr);
		IRI updateClass;
		if (updateExpr instanceof Modify) {
			Modify modify = (Modify) updateExpr;
			if (modify.getInsertExpr() == null && modify.getWhereExpr().equals(modify.getDeleteExpr())) {
				updateClass = SP.DELETE_WHERE_CLASS;
			} else {
				updateClass = SP.MODIFY_CLASS;
			}
		} else if (updateExpr instanceof InsertData) {
			updateClass = SP.INSERT_DATA_CLASS;
		} else if (updateExpr instanceof DeleteData) {
			updateClass = SP.DELETE_DATA_CLASS;
		} else if (updateExpr instanceof Load) {
			updateClass = SP.LOAD_CLASS;
		} else if (updateExpr instanceof Clear) {
			updateClass = SP.CLEAR_CLASS;
		} else if (updateExpr instanceof Create) {
			updateClass = SP.CREATE_CLASS;
		} else {
			throw new RDFHandlerException("Unrecognised UpdateExpr: " + updateExpr.getClass());
		}
		handler.handleStatement(valueFactory.createStatement(updateSubj, RDF.TYPE, updateClass));
		if (output.text) {
			handler.handleStatement(valueFactory.createStatement(updateSubj, SP.TEXT_PROPERTY,
					valueFactory.createLiteral(sourceStrings[i])));
		}
		if (output.rdf) {
			SpinVisitor visitor = new SpinVisitor(handler, null, updateSubj, dataset);
			updateExpr.visit(visitor);
			visitor.end();
		}
	}
	handler.endRDF();
}
 

@Override
public void handleStatement(Statement st) throws RDFHandlerException {
	for (RDFHandler rdfHandler : rdfHandlers) {
		rdfHandler.handleStatement(st);
	}
}