/*
 * (c) Copyright 2007, 2008, 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 * [See end of file]
 */

package search;

import java.util.Iterator ;

import org.openjena.atlas.iterator.Iter ;
import org.openjena.atlas.iterator.Transform ;

import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.query.QueryExecException ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.ExecutionContext ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.engine.binding.BindingFactory ;
import com.hp.hpl.jena.sparql.engine.iterator.QueryIterPlainWrapper ;
import com.hp.hpl.jena.sparql.pfunction.PropFuncArg ;
import com.hp.hpl.jena.sparql.pfunction.PropFuncArgType ;
import com.hp.hpl.jena.sparql.pfunction.PropertyFunctionEval ;

public abstract class BaseSearchPF extends PropertyFunctionEval
{
    public BaseSearchPF()
    {
        super(PropFuncArgType.PF_ARG_SINGLE, PropFuncArgType.PF_ARG_SINGLE) ;
    }

    protected abstract Search searchEngine() ;
    
    @Override
    public QueryIterator execEvaluated(final Binding binding, PropFuncArg argSubject, Node predicate, PropFuncArg argObject,
                                       ExecutionContext execCxt)
    {
        // check subject is a variable.
        if ( ! argSubject.getArg().isVariable() )
            throw new QueryExecException("Subject not a variable") ;
        
        final Var var = Var.alloc(argSubject.getArg()) ;
        
        if ( ! argObject.getArg().isLiteral() )
            throw new QueryExecException("Subject not a literal") ;

        String searchTerm = argObject.getArg().getLiteralLexicalForm() ;
        Search search = searchEngine() ;
        Iterator<String> x = search.search(searchTerm) ;
        Iter<String> iter = Iter.iter(x) ;
        
        Transform<String , Binding> converter = new Transform<String , Binding>(){

            @Override
            public Binding convert(String item)
            {
                return BindingFactory.binding(binding, var, Node.createURI(item)) ;
            }} ;
        QueryIterator qIter = new QueryIterPlainWrapper(iter.map(converter)) ;
        return qIter ;
    }

}

/*
 * (c) Copyright 2007, 2008, 2009 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.
 */