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* 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 arq.examples;
import com.hp.hpl.jena.query.Query ;
import com.hp.hpl.jena.query.QueryFactory ;
import com.hp.hpl.jena.sparql.algebra.Algebra ;
import com.hp.hpl.jena.sparql.algebra.Op ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
/** Simple example to show parsing a query and producing the
* SPARQL agebra expression for the query. */
public class AlgebraEx
{
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, Ex1.createModel()) ;
// Results
for ( ; qIter.hasNext() ; )
{
Binding b = qIter.nextBinding() ;
System.out.println(b) ;
}
qIter.close() ;
}
}