traininfoservice/banedk/MetroServlet.java

package dk.thoerup.traininfoservice.banedk;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
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;
import dk.thoerup.traininfoservice.Statistics;


@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) {
                        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();

                ByteArrayOutputStream out = new ByteArrayOutputStream();

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