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	torben	1041	package dk.thoerup.traininfoservice.banedk;
2
3	torben	1060	import java.io.ByteArrayOutputStream;
4	torben	1041	import java.io.IOException;
5	torben	1042	import java.util.logging.Level;
6	torben	1041	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	torben	1060	import org.simpleframework.xml.Serializer;
15			import org.simpleframework.xml.core.Persister;
16
17	torben	1061	import dk.thoerup.android.traininfo.common.MetroBean;
18	torben	1042	import dk.thoerup.circuitbreaker.CircuitBreakerException;
19			import dk.thoerup.traininfoservice.Statistics;
20	torben	1041
21
22	torben	1042
23	torben	1060
24	torben	1041	@WebServlet(urlPatterns={"/MetroServlet"})
25			public class MetroServlet extends HttpServlet {
26	torben	1042
27			private static final long serialVersionUID = 1L;
28
29			Logger logger = Logger.getLogger(MetroServlet.class.getName());
30	torben	1041
31	torben	1042	MetroFetcher fetcher = new MetroFetcher();
32	torben	1041
33	torben	1042	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
34	torben	1041
35	torben	1042	if (req.getParameter("station") == null) {
36			resp.sendError(400, "not enough parameters");
37			return;
38			}
39	torben	1041
40	torben	1042	//TODO: How should statistics be handled for the metro
41			//Statistics.getInstance().incrementDepartureLookups();
42	torben	1041
43	torben	1042	int station = Integer.parseInt( req.getParameter("station") );
44	torben	1041
45
46	torben	1042	MetroBean bean;
47	torben	1041
48	torben	1042	try {
49	torben	1041
50	torben	1042	bean = fetcher.cachedLookupMetroDepartures(station);
51			String xml = formatXml(bean);
52	torben	1041
53	torben	1042	resp.setDateHeader("Expires", 0);
54			resp.setHeader("Cache-Control", "no-cache, must-revalidate");
55	torben	1060	resp.setContentType("text/xml");
56	torben	1042	resp.getWriter().print(xml);
57	torben	1041
58	torben	1042	} 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	torben	1041	}
74
75
76			}
77
78	torben	1060	String formatXml(MetroBean metro) throws ServletException {
79	torben	1042
80	torben	1060	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	torben	1042	}
89
90	torben	1060	return out.toString();
91	torben	1042	}
92
93	torben	1041	}