Java Code Examples for com.hp.hpl.jena.graph.Node#isURI()

/**
 * Pretty-prints an RDF node and shortens URIs into QNames according to a
 * {@link PrefixMapping}.
 * @param n An RDF node
 * @return An N-Triples style textual representation with URIs shortened to QNames
 */
public static String toString(Node n, PrefixMapping prefixes) {
	if (n.isURI()) {
		return qNameOrURI(n.getURI(), prefixes);
	}
	if (n.isBlank()) {
		return "_:" + n.getBlankNodeLabel();
	}
	if (n.isVariable()) {
		return "?" + n.getName();
	}
	if (Node.ANY.equals(n)) {
		return "?ANY";
	}
	// Literal
	String s = "\"" + n.getLiteralLexicalForm() + "\"";
	if (!"".equals(n.getLiteralLanguage())) {
		s += "@" + n.getLiteralLanguage();
	}
	if (n.getLiteralDatatype() != null) {
		s += "^^" + qNameOrURI(n.getLiteralDatatypeURI(), prefixes);
	}
	return s;
}
 

/**
 * Transforms a Jena node into a java object. Possible node types: uri,
 * variable, literal (datatype, languageTag), blank node
 * 
 * @param n The node to transform
 * @return A specific java object
 * @throws ModelRuntimeException from the underlying model
 */
public static org.ontoware.rdf2go.model.node.Node toRDF2Go(Node n) throws ModelRuntimeException {
	// A return of null indicates that the variable is not present in this
	// solution.
	if(n == null)
		return null;
	
	if(n.isURI())
		return new URIImpl(n.getURI());
	
	if(n.isVariable())
		throw new RuntimeException("Cannot convert a Jena variable to an RDF2Go node");
	
	if(n.isLiteral()) {
		LiteralLabel lit = n.getLiteral();
		// datatype
		if(lit.getDatatypeURI() != null) {
			return new DatatypeLiteralImpl(lit.getLexicalForm(), new URIImpl(
			        lit.getDatatypeURI()));
		}
		
		// language tagged
		if(lit.language() != null && !lit.language().equals(""))
			return new LanguageTagLiteralImpl(lit.getLexicalForm(), lit.language());
		
		// plain
		return new PlainLiteralImpl(lit.getLexicalForm());
	}
	
	if(n.isBlank())
		return new JenaBlankNode(n);
	
	// none of the above - don't know how to transform that
	throw new RuntimeException("no transformation defined from " + n + " to java");
}
 

/**
 * Returns a {@link String} representation of the given {@link Node}.
 * 
 * @param node the node.
 * @return a {@link String} representation of the given {@link Node}.
 */
public static String asNt(final Node node) {
	if (node.isURI()) {
		return asNtURI(node);
	} else if (node.isBlank()) {
		return asNtBlankNode(node);		
	} else if (node.isLiteral()) {
		return asNtLiteral(node);
	}
	throw new IllegalArgumentException(node.getClass().getName());
}
 

/**
 * Find the given triple(s) from the graph. 
 */
@Override
public ExtendedIterator<Triple> find(Node subject, Node predicate, Node object) {
	//System.out.println("NeoGraph#find");
	try(Transaction tx = graphdb.beginTx()) {
		StringBuffer query = new StringBuffer("MATCH triple=");
		
		query.append("(subject");
		if(subject.equals(Node.ANY)) {
			query.append(":"+ LABEL_URI);
			//System.out.println("NeoGraph#find#Any:"+subject);
		} else if(subject.isURI()){
			query.append(":"+LABEL_URI+" {uri:'");
			query.append(subject.getURI());
			query.append("'}");
			//System.out.println("NeoGraph#find#URI:"+subject+subject.getURI());
		} else {
			query.append(":" + LABEL_BNODE);
			//System.out.println("NeoGraph#find#"+subject);
		}
		query.append(")-[predicate]->(object");
		
		//query.append("]->(object");
		if(object.equals(Node.ANY)) {
			//query.append(" ");
		} else if(object.isURI()){
			query.append(":"+LABEL_URI+" {uri:'");
			query.append(object.getURI());
			query.append("'}");
		} else {
			query.append(":"+LABEL_LITERAL+" {value:'");
			query.append(object.getLiteralValue());
			query.append("'}");
		}
		query.append(")");
		
		//System.out.println("Predicate in query: " +getPrefixMapping().shortForm(predicate.getURI()));
		if(predicate.isURI()) {
			query.append("WHERE type(predicate)='");
			query.append(getPrefixMapping().shortForm(predicate.getURI()));
			query.append("'");
		}
		
		query.append("\nRETURN subject, type(predicate), object");
		//System.out.println(query.toString());
		ExecutionEngine engine = new ExecutionEngine(graphdb);
		ExecutionResult results = engine.execute(query.toString());
		//System.out.println(results.dumpToString());
		//System.out.println("NeoGraph#find#"+predicate);
		//System.out.println("NeoGraph#find#"+object);
		//System.out.println("NeoGraph#find#DONE");
		return new ExecutionResultIterator(results, graphdb);
	}
}
 

private List<TripleBean> moreThenOneQuery(QueryExecution qe, List<TripleBean> results, int retry, String overrideProperty) throws Exception {

		try {
			ResultSet rs = qe.execSelect();
			while (rs.hasNext()) {
				TripleBean rb = new TripleBean();
				QuerySolution qs = rs.next();
				String property = "";
				if (overrideProperty != null) {
					property = overrideProperty;
				} else if (qs.get("p") != null) {
					property = qs.get("p").asNode().toString();
				}

				try {
					if (qs.get("s") != null && !qs.get("s").asNode().toString().startsWith("http://")) { // probably
																											// a
																											// bn
						rb.setIRI(qs.get("s").asNode().toString());
						rb.setNsIRI("_:" + rb.getIRI());
					} else if (qs.get("s") != null && qs.get("s").asNode().toString().startsWith("http://")) {
						rb.setIRI(qs.get("s").asNode().toString());
						rb.setNsIRI(Misc.toNsResource(rb.getIRI(), conf));
						rb.setUrl(Misc.toBrowsableUrl(rb.getIRI(), conf));
					}

					PropertyBean p = new PropertyBean();
					p.setNsProperty(Misc.toNsResource(property, conf));
					p.setProperty(property);
					if (ontoBean != null) {
						p.setLabel(ontoBean.getEscapedValue("label", locale, property));
						p.setComment(ontoBean.getEscapedValue("comment", locale, property));
					}
					p.setPropertyUrl(Misc.toBrowsableUrl(property, conf));
					rb.setProperty(p);
					if (qs.get("o") != null) {
						Node object = qs.get("o").asNode();
						if (object.isURI()) {
							rb.setType("iri");
							rb.setValue(object.toString(false));
						} else if (object.isLiteral()) {
							rb.setType("literal");
							rb.setDataType(object.getLiteralDatatypeURI());
							rb.setNsDataType(Misc.toNsResource(object.getLiteralDatatypeURI(), conf));
							rb.setLang(object.getLiteralLanguage());
							rb.setValue(object.getLiteralLexicalForm());
						} else if (object.isBlank()) {
							rb.setType("bnode");
							rb.setValue(object.toString(false));
						}
					} else {
						rb.setType("literal");
						rb.setValue("");
					}
					results.add(rb);
				} catch (Exception e) {
					System.err.println("error? " + e.getMessage());
					// e.printStackTrace();
				}
			}
		} catch (Exception ez) {
			if (retry < 3) {
				retry++;
				// System.out.println("query failed (" + ez.getMessage() +
				// "), I'm giving another chance (" + retry + "/3)");
				return moreThenOneQuery(qe, results, retry, overrideProperty);
			}
			ez.printStackTrace();
			throw new Exception("connection refused");
		}

		return results;
	}
 

public boolean matches(Node node) { return node.isURI(); }