Java Code Examples for org.apache.jena.sparql.engine.QueryIterator#nextBinding()

@Test
public void matchSubjectInSubjectTriple()
{
	// << ?V1 ex:p ex:o >> ex:m1 ex:x1
	final Triple tp1 = new Triple( $V1(), $p(), $o() );
	final Node nTP1 = new Node_TripleStarPattern( tp1 );
	final Triple tp2 = new Triple( nTP1, $m1(), $x1() );

	final Binding inputBinding = BindingFactory.binding();
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp2, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 1, outputBinding.size() );
	assertEquals( $V1(), outputBinding.vars().next() );

	assertEquals( $s(), outputBinding.get($V1()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchSubjectInSubjectTripleWithGivenObjectInMetaTriple()
{
	// << ?V1 ex:p ex:o >> ex:m1 ?V2
	final Triple tp1 = new Triple( $V1(), $p(), $o() );
	final Node nTP1 = new Node_TripleStarPattern( tp1 );
	final Triple tp2 = new Triple( nTP1, $m1(), $V2() );

	// ?V2 --> ex:x1
	final Binding inputBinding = BindingFactory.binding( $V2(), $x1() );
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp2, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 2, outputBinding.size() );

	assertEquals( $s(), outputBinding.get($V1()) );
	assertEquals( $x1(), outputBinding.get($V2()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchObjectRequiresRedundancyAugmentation()
{
	// ex:s ex:p ?V3
	final Triple tp = new Triple( $s(), $p(), $V3() );

	final Binding inputBinding = BindingFactory.binding();
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 1, outputBinding.size() );

	assertEquals( $o(), outputBinding.get($V3()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchSubjectWithGivenObjectRequiresRedundancyAugmentation()
{
	// ?V1 ex:p ?V3
	final Triple tp = new Triple( $V1(), $p(), $V3() );

	// ?V3 --> ex:x1
	final Binding inputBinding = BindingFactory.binding( $V3(), $o() );
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 2, outputBinding.size() );

	assertEquals( $s(), outputBinding.get($V1()) );
	assertEquals( $o(), outputBinding.get($V3()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

public static void main(String []args)
{
    String s = "SELECT DISTINCT ?s { ?s ?p ?o }";
    
    // Parse
    Query query = QueryFactory.create(s) ;
    System.out.println(query) ;
    
    // Generate algebra
    Op op = Algebra.compile(query) ;
    op = Algebra.optimize(op) ;
    System.out.println(op) ;
    
    // Execute it.
    QueryIterator qIter = Algebra.exec(op, ExQuerySelect1.createModel()) ;
    
    // Results
    for ( ; qIter.hasNext() ; )
    {
        Binding b = qIter.nextBinding() ;
        System.out.println(b) ;
    }
    qIter.close() ;
}
 

@Test
public void matchWholeSubjectTriple()
{
	// ?V1 ex:m1 ex:x1
	final Triple tp = new Triple( $V1(), $m1(), $x1() );

	final ExecutionContext execCxt = createTestExecCxt();
	final Binding inputBinding = BindingFactory.binding();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 1, outputBinding.size() );
	assertEquals( $V1(), outputBinding.vars().next() );

	final Node outputValue = outputBinding.get( $V1() );  
	assertTrue( outputValue instanceof Node_Triple );

	final Triple outputTriple = ( (Node_Triple) outputValue ).get();
	assertEquals( $s(), outputTriple.getSubject() );
	assertEquals( $p(), outputTriple.getPredicate() );
	assertEquals( $o(), outputTriple.getObject() );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchWholeObjectTriple()
{
	// ex:x1 ex:m1 ?V1
	final Triple tp = new Triple( $x1(), $m1(), $V1() );

	final ExecutionContext execCxt = createTestExecCxt();
	final Binding inputBinding = BindingFactory.binding();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 1, outputBinding.size() );
	assertEquals( $V1(), outputBinding.vars().next() );

	final Node outputValue = outputBinding.get( $V1() );  
	assertTrue( outputValue instanceof Node_Triple );

	final Triple outputTriple = ( (Node_Triple) outputValue ).get();
	assertEquals( $s(), outputTriple.getSubject() );
	assertEquals( $p(), outputTriple.getPredicate() );
	assertEquals( $o(), outputTriple.getObject() );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchMetaTriplesBasedOnWholeSubjectTriple()
{
	//  << ex:s ex:p ex:o >> ?V1 ?V2
	final Triple tp1 = new Triple( $s(), $p(), $o() );
	final Node nTP1 = new Node_TripleStarPattern( tp1 );
	final Triple tp2 = new Triple( nTP1, $V1(), $V2() );

	final Binding inputBinding = BindingFactory.binding();
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp2, execCxt );
	assertTrue( it.hasNext() );

	Binding outputBinding = null;

	outputBinding = it.nextBinding();
	assertEquals( 2, outputBinding.size() );

	assertEquals( $m1(), outputBinding.get($V1()) );
	assertEquals( $x2(), outputBinding.get($V2()) );

	outputBinding = it.nextBinding();
	assertEquals( 2, outputBinding.size() );

	assertEquals( $m1(), outputBinding.get($V1()) );
	assertEquals( $x1(), outputBinding.get($V2()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchSubjectInSubjectTripleAndObjectInMetaTriple()
{
	// << ?V1 ex:p ex:o >> ex:m1 ?V2
	final Triple tp1 = new Triple( $V1(), $p(), $o() );
	final Node nTP1 = new Node_TripleStarPattern( tp1 );
	final Triple tp2 = new Triple( nTP1, $m1(), $V2() );

	final Binding inputBinding = BindingFactory.binding();
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp2, execCxt );
	assertTrue( it.hasNext() );

	Binding outputBinding = it.nextBinding();
	assertEquals( 2, outputBinding.size() );

	assertEquals( $s(), outputBinding.get($V1()) );
	assertEquals( $x2(), outputBinding.get($V2()) );

	outputBinding = it.nextBinding();
	assertEquals( 2, outputBinding.size() );

	assertEquals( $s(), outputBinding.get($V1()) );
	assertEquals( $x1(), outputBinding.get($V2()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchSubjectInMetaTripleWithGivenObjectInObjectTriple()
{
	// ?V1 ?V2 << ex:s ex:p ?V3 >>
	final Triple tp1 = new Triple( $s(), $p(), $V3() );
	final Node nTP1 = new Node_TripleStarPattern( tp1 );
	final Triple tp2 = new Triple( $V1(), $V2(), nTP1 );

	// ?V3 --> ex:o
	final Binding inputBinding = BindingFactory.binding( $V3(), $o() );
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp2, execCxt );
	assertTrue( it.hasNext() );

	Binding outputBinding = it.nextBinding();
	assertEquals( 3, outputBinding.size() );

	assertEquals( $x2(), outputBinding.get($V1()) );
	assertEquals( $m2(), outputBinding.get($V2()) );
	assertEquals( $o(), outputBinding.get($V3()) );

	outputBinding = it.nextBinding();
	assertEquals( 3, outputBinding.size() );

	assertEquals( $x1(), outputBinding.get($V1()) );
	assertEquals( $m1(), outputBinding.get($V2()) );
	assertEquals( $o(), outputBinding.get($V3()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

@Test
public void matchSubjectInMetaTripleWithGivenSubjectInObjectTriple()
{
	// ?V1 ?V2 << ?V3 ex:p ex:o >>
	final Triple tp1 = new Triple( $s(), $p(), $V3() );
	final Node nTP1 = new Node_TripleStarPattern( tp1 );
	final Triple tp2 = new Triple( $V1(), $V2(), nTP1 );

	// ?V2 --> ex:m1, ?V3 --> ex:s
	final Binding inputBindingX = BindingFactory.binding( $V2(), $m1() );
	final Binding inputBinding = BindingFactory.binding( inputBindingX, $V3(), $o() );
	final ExecutionContext execCxt = createTestExecCxt();
	final QueryIterator input = QueryIterSingleton.create(inputBinding, execCxt);

	final QueryIterator it = QueryIterTripleStarPattern.create( input, tp2, execCxt );
	assertTrue( it.hasNext() );

	final Binding outputBinding = it.nextBinding();
	assertEquals( 3, outputBinding.size() );

	assertEquals( $x1(), outputBinding.get($V1()) );
	assertEquals( $m1(), outputBinding.get($V2()) );
	assertEquals( $o(), outputBinding.get($V3()) );

	assertFalse( it.hasNext() ); 
	it.close();
}
 

public static void main (String[] argv)
{
    String BASE = "http://example/" ; 
    BasicPattern bp = new BasicPattern() ;
    Var var_x = Var.alloc("x") ;
    Var var_z = Var.alloc("z") ;
    
    // ---- Build expression
    bp.add(new Triple(var_x, NodeFactory.createURI(BASE+"p"), var_z)) ;
    Op op = new OpBGP(bp) ;
    //Expr expr = ExprUtils.parse("?z < 2 ") ;
    Expr expr = new E_LessThan(new ExprVar(var_z), NodeValue.makeNodeInteger(2)) ;
    op = OpFilter.filter(expr, op) ;

    // ---- Example setup
    Model m = makeModel() ;
    m.write(System.out, "TTL") ;
    System.out.println("--------------") ;
    System.out.print(op) ;
    System.out.println("--------------") ;

    // ---- Execute expression
    QueryIterator qIter = Algebra.exec(op, m.getGraph()) ;
    
    // -------- Either read the query iterator directly ...
    if ( false )
    {
        for ( ; qIter.hasNext() ; )
        {
            Binding b = qIter.nextBinding() ;
            Node n = b.get(var_x) ;
            System.out.println(NodeFmtLib.displayStr(n)) ;
            System.out.println(b) ; 
        }
        qIter.close() ;
    }
    else
    {
        // -------- Or make ResultSet from it (but not both - reading an
        //          iterator consumes the current solution)
        List<String> varNames = new ArrayList<String>() ;
        varNames.add("x") ;
        varNames.add("z") ;
        ResultSet rs = new ResultSetStream(varNames, m, qIter);
        ResultSetFormatter.out(rs) ;
        qIter.close() ;
    }
    System.exit(0) ;
}