`/*
* (c) Copyright 2008 Hewlett-Packard Development Company, LP
* All rights reserved.
* [See end of file]
*/
package arq.examples.bgpmatching;
import java.util.Iterator;
import com.hp.hpl.jena.graph.Triple;
import com.hp.hpl.jena.graph.impl.GraphBase;
import com.hp.hpl.jena.sparql.core.BasicPattern;
import com.hp.hpl.jena.sparql.engine.ExecutionContext;
import com.hp.hpl.jena.sparql.engine.QueryIterator;
import com.hp.hpl.jena.sparql.engine.iterator.QueryIterTriplePattern;
import com.hp.hpl.jena.sparql.engine.main.StageGenerator;
/** Example stage generator that compiles a BasicPattern into a sequence of
* individual triple matching steps.
*/
public class StageGeneratorAlt implements StageGenerator
{
StageGenerator other ;
public StageGeneratorAlt(StageGenerator other)
{
this.other = other ;
}
public QueryIterator execute(BasicPattern pattern,
QueryIterator input,
ExecutionContext execCxt)
{
// Just want to pick out some BGPs (e.g. on a particualr graph)
// Test :: execCxt.getActiveGraph()
if ( ! ( execCxt.getActiveGraph() instanceof GraphBase ) )
// Example: pass on up to the original StageGenerator if
// not based on GraphBase (which most Graph implementations are).
return other.execute(pattern, input, execCxt) ;
System.err.println("MyStageGenerator.compile:: triple patterns = "+pattern.size()) ;
// Stream the triple matches together, one triple matcher at a time.
QueryIterator qIter = input ;
for ( Iterator iter = pattern.getList().iterator() ; iter.hasNext() ; )
{
Triple triple = (Triple)iter.next();
qIter = new QueryIterTriplePattern(qIter, triple, execCxt) ;
}
return qIter ;
}
}
/*
* (c) Copyright 2008 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.
*/`