/**
 * Creates an RDF model of publications and vcards, then uses RDQL
 * to query the model.
 *
 * WARNING: The query classes are very sensitive to the format of the 
 * query string.  
 */

//Java IO classes.
import java.io.PrintWriter;
import java.io.Writer;
import java.io.InputStreamReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.OutputStream;

//Java utility classes
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.Iterator;

//The Dublin Core
import com.hp.hpl.mesa.rdf.jena.vocabulary.DC;

//The VCARD class
import com.hp.hpl.mesa.rdf.jena.vocabulary.VCARD;

//Use the memory model implementation
import com.hp.hpl.mesa.rdf.jena.mem.ModelMem;

//Model package imports
import com.hp.hpl.mesa.rdf.jena.model.Model;
import com.hp.hpl.mesa.rdf.jena.model.Resource;
import com.hp.hpl.mesa.rdf.jena.model.Literal;
import com.hp.hpl.mesa.rdf.jena.model.Property; 
import com.hp.hpl.mesa.rdf.jena.model.Statement; 
import com.hp.hpl.mesa.rdf.jena.model.StmtIterator;
import com.hp.hpl.mesa.rdf.jena.model.RDFNode;
import com.hp.hpl.mesa.rdf.jena.model.RDFException;
import com.hp.hpl.mesa.rdf.jena.model.ResIterator;

//RDQL imports
import com.hp.hpl.jena.rdf.query.Query;
import com.hp.hpl.jena.rdf.query.QueryExecution;
import com.hp.hpl.jena.rdf.query.QueryEngine;
import com.hp.hpl.jena.rdf.query.QueryResults;
import com.hp.hpl.jena.rdf.query.ResultBinding;

public class DublinCoreEx7 {
    //Some URIs for people with VCARDS.
    String[] nameUris={"http://cgl.indiana.edu/people/GCF",
		       "http://cgl.indiana.edu/people/MEP",
		       "http://cgl.indiana.edu/people/DBC"};
    
    //Some URIs for VCARDs.
    Model model=null;
    DublinCoreEx5 dc5;
    public DublinCoreEx7() throws Exception {
	model=new ModelMem();
	new DublinCoreEx7(model);
    }
    
    public DublinCoreEx7(Model model) throws Exception {
 	this.model=model;
	//	model.read(new FileReader("people.rdf"),"");
	
  	dc5=new DublinCoreEx5(model);
 	dc5.init();
	//	dc5.printRDFXML(model,System.out);	
    }

    //Process a query string
    public QueryResults processQuery(String queryString) 
	throws RDFException{
	Query query=new Query(queryString);
	query.setSource(model);
	QueryExecution qe=new QueryEngine(query);
	QueryResults results=qe.exec();

	return results;
    }

    //Print the results of the query
    public void printQueryResults(QueryResults results) {
	for(Iterator iter=results;iter.hasNext();) {
	    ResultBinding res=(ResultBinding)iter.next();
	    Resource r=(Resource)res.get("x");
	    Literal l=(Literal)res.get("fname");
	    System.out.println(r+" "+l);
	}
	//Must call close() to get any results.
	results.close();
    }
    
    public static void main(String[] args) throws Exception{
	Model model=new ModelMem();
	DublinCoreEx7 dc7=new DublinCoreEx7(model);
	String queryString = "SELECT ?x, ?fname "+
	    "WHERE (?x, <http://www.w3.org/2001/vcard-rdf/3.0#EMAIL>, ?fname)" ;
	dc7.printQueryResults(dc7.processQuery(queryString));
	
    }
}