Examples with ElementFilter org.apache.jena.sparql.syntax.ElementFilter used on opensource projects

Example 6 with ElementFilter

use of org.apache.jena.sparql.syntax.ElementFilter in project jena by apache.

the class WhereHandlerTest method testAddFilterWithNamespace.

@Test
public void testAddFilterWithNamespace() throws ParseException {
    query.setPrefix("afn", "http://jena.apache.org/ARQ/function#");
    handler.addFilter("afn:namespace(?one) = 'foo'");
    handler.build();
    ExprFactory fact = new ExprFactory();
    E_Function func = new E_Function("http://jena.apache.org/ARQ/function#namespace", fact.asList("?one"));
    E_Equals expr = fact.eq(func, "foo");
    WhereValidator visitor = new WhereValidator(new ElementFilter(expr));
    handler.getQueryPattern().visit(visitor);
    assertTrue(visitor.matching);
}

Example 7 with ElementFilter

use of org.apache.jena.sparql.syntax.ElementFilter in project jena by apache.

the class WhereClauseTest method testAddFilter.

@ContractTest
public void testAddFilter() throws ParseException {
    WhereClause<?> whereClause = getProducer().newInstance();
    AbstractQueryBuilder<?> builder = whereClause.addFilter("?one<10");
    E_LessThan lt = new E_LessThan(new ExprVar(Var.alloc("one")), new NodeValueInteger(10));
    ElementFilter ef = new ElementFilter(lt);
    WhereValidator visitor = new WhereValidator(ef);
    builder.build().getQueryPattern().visit(visitor);
    assertTrue(visitor.matching);
}

Example 8 with ElementFilter

use of org.apache.jena.sparql.syntax.ElementFilter in project jena by apache.

the class labelSearch method buildSyntax.

// Build SPARQL syntax and compile it.
// Not recommended.
private QueryIterator buildSyntax(QueryIterator input, Node nodeVar, String pattern, ExecutionContext execCxt) {
    Var var2 = createNewVar();
    // Triple patterns for   ?x rdfs:label ?hiddenVar
    ElementTriplesBlock elementBGP = new ElementTriplesBlock();
    Triple t = new Triple(nodeVar, RDFS.label.asNode(), var2);
    elementBGP.addTriple(t);
    // Regular expression for  regex(?hiddenVar, "pattern", "i")
    Expr regex = new E_Regex(new ExprVar(var2.getName()), pattern, "i");
    ElementGroup elementGroup = new ElementGroup();
    elementGroup.addElement(elementBGP);
    elementGroup.addElement(new ElementFilter(regex));
    // Compile it.
    // The better design is to build the Op structure programmatically,
    Op op = Algebra.compile(elementGroup);
    op = Algebra.optimize(op, execCxt.getContext());
    return QC.execute(op, input, execCxt);
}

Example 9 with ElementFilter

use of org.apache.jena.sparql.syntax.ElementFilter in project jena by apache.

the class ExProg2 method main.

public static void main(String[] args) {
    Model model = createModel();
    Query query = QueryFactory.make();
    query.setQuerySelectType();
    // See also ExProg1
    ElementGroup elg = new ElementGroup();
    Var varTitle = Var.alloc("title");
    Var varX = Var.alloc("x");
    Triple t1 = new Triple(varX, DC.title.asNode(), varTitle);
    elg.addTriplePattern(t1);
    // Adds a filter.  Need to wrap variable in a NodeVar.
    Expr expr = new E_Regex(new ExprVar(varTitle), "sparql", "i");
    ElementFilter filter = new ElementFilter(expr);
    elg.addElementFilter(filter);
    // Attach the group to query.
    query.setQueryPattern(elg);
    // Choose what we want - SELECT ?title
    query.addResultVar(varTitle);
    // Print query with line numbers
    // Prefix mapping just helps serialization
    query.getPrefixMapping().setNsPrefix("dc", DC.getURI());
    query.serialize(new IndentedWriter(System.out, true));
    System.out.println();
    try (QueryExecution qexec = QueryExecutionFactory.create(query, model)) {
        // Assumption: it's a SELECT query.
        ResultSet rs = qexec.execSelect();
        // The order of results is undefined.
        System.out.println("Titles: ");
        for (; rs.hasNext(); ) {
            QuerySolution rb = rs.nextSolution();
            // Get title - variable names do not include the '?' (or '$')
            RDFNode x = rb.get("title");
            // Check the type of the result value
            if (x instanceof Literal) {
                Literal titleStr = (Literal) x;
                System.out.println("    " + titleStr);
            } else
                System.out.println("Strange - not a literal: " + x);
        }
    }
}