algebraex.java

jena2.5.4推理机系统的一种最基本实现 HP实验室出品

/*
 * (c) Copyright 2007 Hewlett-Packard Development Company, LP
 * All rights reserved.
 * [See end of file]
 */

package arq.examples;

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;

import com.hp.hpl.jena.query.Query;
import com.hp.hpl.jena.query.QueryFactory;

/** Simple example to show parsing a query and producing the
 *  SPARQL agebra expression for the query.
 * @author Andy Seaborne
 * @version $Id: AlgebraEx.java,v 1.3 2007/09/06 15:12:10 andy_seaborne Exp $
 */
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) ;
        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() ;
    }
}

/*
 * (c) Copyright 2007 Hewlett-Packard Development Company, LP
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */