/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.sparql.pfunction.library;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.NodeFactory ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.engine.ExecutionContext ;
import org.apache.jena.sparql.engine.QueryIterator ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.expr.ExprEvalException ;
import org.apache.jena.sparql.pfunction.PFuncSimple ;
import org.apache.jena.sparql.util.IterLib ;
/** Relationship between a node (subject) and it's bNode label (object/string) */
public class blankNode extends PFuncSimple
{
@Override
public QueryIterator execEvaluated(Binding binding, Node subject, Node predicate, Node object, ExecutionContext execCxt)
{
if ( Var.isVar(subject) )
throw new ExprEvalException("bnode: subject is an unbound variable") ;
if ( ! subject.isBlank() )
return IterLib.noResults(execCxt) ;
String str = subject.getBlankNodeLabel() ;
Node obj = NodeFactory.createLiteral(str) ;
if ( Var.isVar(object) )
return IterLib.oneResult(binding, Var.alloc(object), obj, execCxt) ;
// Subject and object are concrete
if ( object.sameValueAs(obj) )
return IterLib.result(binding, execCxt) ;
return IterLib.noResults(execCxt) ;
}
}