Java RepositoryConnection.prepareTupleQuery方法代碼示例

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Get total number of distinct objects for a predicate
 * @param pred Predicate
 * @param m model
 * @return triples
 */
public static long getDistinctObj(String pred, String endpoint) throws Exception {
	String strQuery = "SELECT  (COUNT(DISTINCT ?o) AS ?objs) " + // 
			"WHERE " +
			"{" +
       		"?s <" + pred + "> ?o " +
       		"} " ;
	SPARQLRepository repo = new SPARQLRepository(endpoint);
	repo.initialize();
	RepositoryConnection conn = repo.getConnection();
	try {
		TupleQuery query = conn.prepareTupleQuery(QueryLanguage.SPARQL, strQuery); 
		TupleQueryResult rs = query.evaluate();
		return Long.parseLong(rs.next().getValue("objs").stringValue());
	} finally {
		conn.close();
		repo.shutDown();
	}
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Get total number of distinct objects for a predicate
 * @param pred Predicate
 * @param m model
 * @return triples
 */
public static long getDistinctSbj(String pred, String endpoint) throws Exception {
	String strQuery = "SELECT  (COUNT(DISTINCT ?s) AS ?subjs) " + // 
			"WHERE " +
			"{" +
       		"?s <" + pred + "> ?o " +
       		"} " ;
	SPARQLRepository repo = new SPARQLRepository(endpoint);
	repo.initialize();
	RepositoryConnection conn = repo.getConnection();
	try {
		TupleQuery query = conn.prepareTupleQuery(QueryLanguage.SPARQL, strQuery); 
		TupleQueryResult rs = query.evaluate();
		return Long.parseLong(rs.next().getValue("subjs").stringValue());
	} finally {
		conn.close();
		repo.shutDown();
	}
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Get total number of distinct subjects of a dataset
 * @return count 
 */
public static long getSubjectCount(String endpoint) throws Exception {
	String strQuery = "SELECT  (COUNT(DISTINCT ?s) AS ?sbjts) " + // 
			"WHERE " +
			"{" +
       		"?s ?p ?o " +
       		"} " ;
	SPARQLRepository repo = new SPARQLRepository(endpoint);
	repo.initialize();
	RepositoryConnection conn = repo.getConnection();
	try {
		TupleQuery query = conn.prepareTupleQuery(QueryLanguage.SPARQL, strQuery); 
		TupleQueryResult rs = query.evaluate();
		return Long.parseLong(rs.next().getValue("sbjts").stringValue());
	} finally {
		conn.close();
		repo.shutDown();
	}
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Get total number of distinct objects of a dataset
 * @return count
 */
public static long getObjectCount(String endpoint) throws Exception {
	String strQuery = "SELECT  (COUNT(DISTINCT ?o) AS ?objts) " + // 
			"WHERE " +
			"{" +
       		"?s ?p ?o " +
       		"} " ;
	SPARQLRepository repo = new SPARQLRepository(endpoint);
	repo.initialize();
	RepositoryConnection conn = repo.getConnection();
	try {
		TupleQuery query = conn.prepareTupleQuery(QueryLanguage.SPARQL, strQuery); 
		TupleQueryResult rs = query.evaluate();
		return Long.parseLong(rs.next().getValue("objts").stringValue());
	} finally {
		conn.close();
		repo.shutDown();
	}
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Get total number of triple for a predicate
 * @param pred Predicate
 * @param m model
 * @return triples
 */
public static Long getTripleCount(String pred, String endpoint) throws Exception {
	String strQuery = "SELECT  (COUNT(?s) AS ?triples) " + // 
			"WHERE " +
			"{" +
       		"?s <"+pred+"> ?o " +
       		"} " ;
	SPARQLRepository repo = new SPARQLRepository(endpoint);
	repo.initialize();
	RepositoryConnection conn = repo.getConnection();
	try {
		TupleQuery query = conn.prepareTupleQuery(QueryLanguage.SPARQL, strQuery); 
		TupleQueryResult rs = query.evaluate();
		return Long.parseLong(rs.next().getValue("triples").stringValue());
	} finally {
		conn.close();
		repo.shutDown();
	}
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Get Predicate List
 * @param endPointUrl SPARQL endPoint Url
 * @param graph Named graph
 * @return  predLst Predicates List
 */
private static List<String> getPredicates(String endPointUrl, String graph) throws Exception
{
	List<String>  predLst = new ArrayList<String>();
	String strQuery = getPredQuery(graph);
	SPARQLRepository repo = new SPARQLRepository(endPointUrl);
	repo.initialize();
	RepositoryConnection conn = repo.getConnection();
	try {
		TupleQuery query = conn.prepareTupleQuery(QueryLanguage.SPARQL, strQuery); 
		TupleQueryResult res = query.evaluate();
		while (res.hasNext()) 
		{
			String pred = res.next().getValue("p").toString();
			predLst.add(pred);	  		
		}
	} finally {
		conn.close();
		repo.shutDown();
	}
	return predLst;
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
/**
 * Execute a SELECT SPARQL query against the graph
 * 
 * @param qs
 *            SELECT SPARQL query
 * @return list of solutions, each containing a hashmap of bindings
 */
public List runSPARQL(String qs) {
	try {
		RepositoryConnection con = therepository.getConnection();
		try {
			TupleQuery query = con.prepareTupleQuery(org.openrdf.query.QueryLanguage.SPARQL, qs);
			TupleQueryResult qres = query.evaluate();
			ArrayList reslist = new ArrayList();
			while (qres.hasNext()) {
				BindingSet b = qres.next();
				Set names = b.getBindingNames();
				HashMap hm = new HashMap();
				for (Object n : names) {
					hm.put((String) n, b.getValue((String) n));
				}
				reslist.add(hm);
			}
			return reslist;
		} finally {
			con.close();
		}
	} catch (Exception e) {
		e.printStackTrace();
	}
	return null;
}
 

import org.openrdf.repository.RepositoryConnection; //導入方法依賴的package包/類
public static final <T> T getSelect( QueryExecutor<T> query,
		RepositoryConnection rc, boolean dobindings ) throws RepositoryException,
		MalformedQueryException, QueryEvaluationException {

	String sparql = processNamespaces( dobindings ? query.getSparql()
			: query.bindAndGetSparql(), query.getNamespaces() );

	ValueFactory vfac = new ValueFactoryImpl();
	TupleQuery tq = rc.prepareTupleQuery( QueryLanguage.SPARQL, sparql );

	if ( null != query.getContext() ) {
		DatasetImpl dataset = new DatasetImpl();
		dataset.addDefaultGraph( query.getContext() );
		tq.setDataset( dataset );
	}

	if ( dobindings ) {
		tq.setIncludeInferred( query.usesInferred() );
		query.setBindings( tq, vfac );
	}

	TupleQueryResult rslt = tq.evaluate();
	query.start( rslt.getBindingNames() );
	while ( rslt.hasNext() ) {
		query.handleTuple( rslt.next(), vfac );
	}
	query.done();
	rslt.close();
	return query.getResults();
}