/src/com/getsemantics/semtools/dbpedia/DBpediaSearch.java

package com.getsemantics.semtools.dbpedia;



import java.io.IOException;

import java.net.MalformedURLException;

import java.net.ProtocolException;

import java.net.SocketTimeoutException;

import java.net.URL;

import java.net.URLConnection;

import java.net.URLEncoder;



import org.apache.log4j.Logger;

import org.apache.log4j.xml.DOMConfigurator;



import com.hp.hpl.jena.rdf.model.Model;

import com.hp.hpl.jena.rdf.model.ModelFactory;



import com.hp.hpl.jena.rdf.model.Resource;



public class DBpediaSearch {

	private static Logger logger = Logger.getLogger(DBPediaQuery.class.getPackage().getName());

	

	private final String prefixes = 

		"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> " + 

		"PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> " +  

		"PREFIX dbp: <http://dbpedia.org/ontology/> " +

		"PREFIX dc: <http://purl.org/dc/elements/1.1/> " +

		"PREFIX dbpedia2: <http://dbpedia.org/property/> ";

	

	

	// get the DBpedia Res

	public DBpediaSearch(){

		DOMConfigurator.configure("logger.xml");

		

	}

	

	public Resource search(String pQuery){

		

		Resource resource = null;

		Model m = query(prefixes+pQuery);

		

		if(m!=null){

			/*

			Model model = resource.getModel();

			Property redirect =  model.getProperty("http://dbpedia.org/property/", "redirect");

			

			if(resource.hasProperty(redirect)){

				String newUri= resource.getProperty(redirect).getResource().getURI();

				q = resourceQuery.replaceAll("DBPEDIA_URI", newUri);

		    	logger.debug("			URIExpand is redirected to " + newUri);

		    	resource = query(q, newUri);

			}

			

			StmtIterator iter = resource.listStatements(new SimpleSelector(resModel.getResource(dbpediaUri), redirect, (RDFNode) null));

			if (iter.hasNext()) {

			    while (iter.hasNext()) {

			    	//UPDATES A NEW URI FROM REDIRECT

			    	dbpediaUri = iter.nextStatement().getObject().toString();

			    	q = resourceQuery.replaceAll("DBPEDIA_URI", dbpediaUri);

			    	logger.debug("	is redirected to " + dbpediaUri);

			    	resModel = query(q, dbpediaUri);

			        

			    }	

			} */

		}

		

		return resource;

	}

	

	public static Model query(String query){



		String 	endpoint 					= "http://dbpedia.org/sparql/?format=application%2Frdf%2Bxml&query=";

		boolean blnSocketTimeoutException	= false;

		int		countSocketTimeoutException	= 0;

		

		Model model = null;

		try {

			// Set up the initial connection

			logger.debug(endpoint + URLEncoder.encode(query, "UTF-8"));

			URL url = new URL(endpoint+URLEncoder.encode(query, "UTF-8"));

			

			do{

				try{

					URLConnection connection = url.openConnection();

					connection.setReadTimeout(30000);

					blnSocketTimeoutException=false;

					connection.connect();

					model = ModelFactory.createDefaultModel();

					model.read(connection.getInputStream(), "");

					// add results to the model

					

				}catch(SocketTimeoutException e){

					blnSocketTimeoutException =true;

					countSocketTimeoutException++;

					logger.info("		RETRY connection " + countSocketTimeoutException);

				}

			}while(blnSocketTimeoutException==true && countSocketTimeoutException<3);

			

			if(blnSocketTimeoutException==true && countSocketTimeoutException==3){

				logger.error("	QUERY FIELD: " + query);

			}

			

		

		} catch (MalformedURLException e) {

			e.printStackTrace();

		} catch (ProtocolException e) {

			e.printStackTrace();

		} catch (IOException e) {

			e.printStackTrace();

		}

		

		return model;

	}

}