traininfoservice/banedk/MetroServlet.java

package dk.thoerup.traininfoservice.banedk;


import java.io.IOException;
import java.io.StringWriter;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.simpleframework.xml.Serializer;
import org.simpleframework.xml.core.Persister;

import dk.thoerup.android.traininfo.common.MetroBean;
import dk.thoerup.circuitbreaker.CircuitBreakerException;


@WebServlet(urlPatterns={"/MetroServlet"})
public class MetroServlet extends HttpServlet {

        private static final long serialVersionUID = 1L;

        Logger logger = Logger.getLogger(MetroServlet.class.getName());
        
        MetroFetcher fetcher = new MetroFetcher();

        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                
                if (req.getParameter("station") == null || req.getParameter("station").equals("") ) {
                        resp.sendError(400, "not enough parameters");
                        return;
                }                       
                
                //TODO: How should statistics be handled for the metro
                //Statistics.getInstance().incrementDepartureLookups(); 
                
                int station = Integer.parseInt( req.getParameter("station") );


                MetroBean bean;         

                try {
                        
                        bean = fetcher.cachedLookupMetroDepartures(station);
                        String xml = formatXml(bean);
                        
                        resp.setDateHeader("Expires", 0);
                        resp.setHeader("Cache-Control", "no-cache, must-revalidate");
                        resp.setContentType("text/xml");
                        resp.getWriter().print(xml);
                        
                } catch (java.io.IOException ioe) {
                        logger.warning("Metro read failed, station="+station + ". " + ioe.getMessage() );
                        //Statistics.getInstance().incrementDepartureErrors();
                        resp.sendError(500);
                        return;
                } catch (CircuitBreakerException cbe) {
                        logger.warning("Circuitbreaker - failing fast");
                        //Statistics.getInstance().incrementDepartureErrors();
                        resp.sendError(500);
                        return;
                } catch (Exception e) {                 
                        logger.log(Level.WARNING, "Unknown exception, metro-station=" +station, e);
                        //Statistics.getInstance().incrementDepartureErrors();
                        resp.sendError(500);
                        return;
                }
                
                
        }
        
        String formatXml(MetroBean metro) throws ServletException {
                
                Serializer serializer = new Persister();

                StringWriter out = new StringWriter();

                try {
                        serializer.write(metro, out);
                } catch (Exception e) {
                        throw new ServletException(e);
                }
                
                return out.toString();
        }
        
}
1	package dk.thoerup.traininfoservice.banedk;
2
3
4	import java.io.IOException;
5	import java.io.StringWriter;
6	import java.util.logging.Level;
7	import java.util.logging.Logger;
8
9	import javax.servlet.ServletException;
10	import javax.servlet.annotation.WebServlet;
11	import javax.servlet.http.HttpServlet;
12	import javax.servlet.http.HttpServletRequest;
13	import javax.servlet.http.HttpServletResponse;
14
15	import org.simpleframework.xml.Serializer;
16	import org.simpleframework.xml.core.Persister;
17
18	import dk.thoerup.android.traininfo.common.MetroBean;
19	import dk.thoerup.circuitbreaker.CircuitBreakerException;
20
21
22
23
24
25	@WebServlet(urlPatterns={"/MetroServlet"})
26	public class MetroServlet extends HttpServlet {
27
28	private static final long serialVersionUID = 1L;
29
30	Logger logger = Logger.getLogger(MetroServlet.class.getName());
31
32	MetroFetcher fetcher = new MetroFetcher();
33
34	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
35
36	if (req.getParameter("station") == null \|\| req.getParameter("station").equals("") ) {
37	resp.sendError(400, "not enough parameters");
38	return;
39	}
40
41	//TODO: How should statistics be handled for the metro
42	//Statistics.getInstance().incrementDepartureLookups();
43
44	int station = Integer.parseInt( req.getParameter("station") );
45
46
47	MetroBean bean;
48
49	try {
50
51	bean = fetcher.cachedLookupMetroDepartures(station);
52	String xml = formatXml(bean);
53
54	resp.setDateHeader("Expires", 0);
55	resp.setHeader("Cache-Control", "no-cache, must-revalidate");
56	resp.setContentType("text/xml");
57	resp.getWriter().print(xml);
58
59	} catch (java.io.IOException ioe) {
60	logger.warning("Metro read failed, station="+station + ". " + ioe.getMessage() );
61	//Statistics.getInstance().incrementDepartureErrors();
62	resp.sendError(500);
63	return;
64	} catch (CircuitBreakerException cbe) {
65	logger.warning("Circuitbreaker - failing fast");
66	//Statistics.getInstance().incrementDepartureErrors();
67	resp.sendError(500);
68	return;
69	} catch (Exception e) {
70	logger.log(Level.WARNING, "Unknown exception, metro-station=" +station, e);
71	//Statistics.getInstance().incrementDepartureErrors();
72	resp.sendError(500);
73	return;
74	}
75
76
77	}
78
79	String formatXml(MetroBean metro) throws ServletException {
80
81	Serializer serializer = new Persister();
82
83	StringWriter out = new StringWriter();
84
85	try {
86	serializer.write(metro, out);
87	} catch (Exception e) {
88	throw new ServletException(e);
89	}
90
91	return out.toString();
92	}
93
94	}