Java Code Examples for org.apache.jena.graph.Node#getName()

/**
 * converts a {@link Node} into an {l@ink Expr}
 * @param n
 * @return
 */
protected Expr	toExpr(Node n) {
	if (n.isVariable()) {
		return new VariableExpr(n.getName());
	} else if (n.isURI()) {
		try {
			return new ConstantExpr(new URI(n.getURI()));
		} catch (URISyntaxException e) {
			throw new RuntimeException(e);
		}
	} else if (n.isLiteral()) {
		Literal l = (Literal) n;
		return new ConstantExpr(l.getValue());
	} else {
		throw new RuntimeException("Unsuported node type in query : "+n);
	}
}
 

protected static E_Equals toEqualsFilter(Expr left, Expr right) {
	Node ln = toNode(left);
	org.apache.jena.sparql.expr.Expr le = ln.isVariable()? new ExprVar(ln.getName()) : new NodeValueNode(ln);
	Node rn = toNode(right);
	org.apache.jena.sparql.expr.Expr re = rn.isVariable()? new ExprVar(rn.getName()) : new NodeValueNode(rn);
	return new E_Equals(le, re);
}
 

protected static E_Equals toIRIEqualsFilter(Expr left, Expr right) {
	Node ln = toNode(left);
	org.apache.jena.sparql.expr.Expr le = ln.isVariable()? new ExprVar(ln.getName()) : new NodeValueNode(ln);
	Node rn = toNode(right);
	org.apache.jena.sparql.expr.Expr re = rn.isVariable()? new ExprVar(rn.getName()) : new NodeValueNode(rn);
	return new E_Equals(new E_Str(le), new E_Str(re));
}
 

protected static E_NotEquals toNotEqualsFilter(Expr left, Expr right) {
	Node ln = toNode(left);
	org.apache.jena.sparql.expr.Expr le = ln.isVariable()? new ExprVar(ln.getName()) : new NodeValueNode(ln);
	Node rn = toNode(right);
	org.apache.jena.sparql.expr.Expr re = rn.isVariable()? new ExprVar(rn.getName()) : new NodeValueNode(rn);
	return new E_NotEquals(le, re);
}
 

protected static E_NotEquals toIRINotEqualsFilter(Expr left, Expr right) {
	Node ln = toNode(left);
	org.apache.jena.sparql.expr.Expr le = ln.isVariable()? new ExprVar(ln.getName()) : new NodeValueNode(ln);
	Node rn = toNode(right);
	org.apache.jena.sparql.expr.Expr re = rn.isVariable()? new ExprVar(rn.getName()) : new NodeValueNode(rn);
	return new E_NotEquals(new E_Str(le), new E_Str(re));
}
 

/***
 * Takes a SELECT query and unroll it into a more complex SPARQL query under
 * rules
 * 
 * @param query
 */
public Query unfold(Query query) {

	ResolutionVisitor visitor = new ResolutionVisitor(rules);
	Op body = Algebra.compile(query);

	OpVariableVistor<String> collector = new OpVariableVistor<String>(body,
			true) {
		@Override
		protected String processVar(Node v) {
			return v.getName();
		}
	};
	OpWalker.walk(body, collector);

	Set<String> bindingNames = new HashSet<String>(collector.getResult());

	visitor.setBindingNames(bindingNames);

	Op newQuery = body;
	newQuery = Transformer.transform(visitor, body);

	
	VarExprList expr = new VarExprList();	
//	E_StrConcat trace = getRuleTracingConcat(newQuery);
	E_StrConcat trace = null;
	
	if (trace!=null) {
		expr.add(Var.alloc("trace"),trace);		
		newQuery = OpExtend.extend(newQuery, expr);
		newQuery = OpJoin.create(newQuery, OpTable.unit());
		
		if (SPARQLRewriterForJena.GENERATE_TRACE_SUMMARY) {
			
			VarExprList groupVars = new VarExprList();
			groupVars.add(Var.alloc("trace"));
			AggCount count = new AggCount();
			ExprAggregator aggregators = new ExprAggregator(Var.alloc("trace.sum"), count);
			List<ExprAggregator> list = new LinkedList<ExprAggregator>();
			list.add(aggregators);
			
			Op groupBy = new OpGroup(newQuery, groupVars, list);
			
			VarExprList expr2 = new VarExprList();	
			expr2.add(Var.alloc("sum"), new ExprVar("trace.sum"));			
			groupBy = OpExtend.extend(groupBy, expr2);
			List<Var> vars = new LinkedList<Var>();
			vars.add(Var.alloc("sum"));
			vars.add(Var.alloc("trace"));
			OpProject project = new OpProject(groupBy, vars);
			newQuery = project;
			
			
		}

	}
	
	
	
	
	
	Query q = OpAsQuery.asQuery(newQuery);
	q.setDistinct(true);	// KAVITHA: Not setting distinct on the consequent leaves duplicates
	return q;

}
 

protected Expr getExpr(Node n) {
	return n.isVariable()? new ExprVar(n.getName()) : new NodeValueNode(n);
}