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) {
                        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	torben	1041	package dk.thoerup.traininfoservice.banedk;
2
3	torben	1190
4	torben	1041	import java.io.IOException;
5	torben	1190	import java.io.StringWriter;
6	torben	1042	import java.util.logging.Level;
7	torben	1041	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	torben	1060	import org.simpleframework.xml.Serializer;
16			import org.simpleframework.xml.core.Persister;
17
18	torben	1061	import dk.thoerup.android.traininfo.common.MetroBean;
19	torben	1042	import dk.thoerup.circuitbreaker.CircuitBreakerException;
20	torben	1041
21
22	torben	1042
23	torben	1060
24	torben	1401
25	torben	1041	@WebServlet(urlPatterns={"/MetroServlet"})
26			public class MetroServlet extends HttpServlet {
27	torben	1042
28			private static final long serialVersionUID = 1L;
29
30			Logger logger = Logger.getLogger(MetroServlet.class.getName());
31	torben	1041
32	torben	1042	MetroFetcher fetcher = new MetroFetcher();
33	torben	1041
34	torben	1042	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
35	torben	1041
36	torben	1042	if (req.getParameter("station") == null) {
37			resp.sendError(400, "not enough parameters");
38			return;
39			}
40	torben	1041
41	torben	1042	//TODO: How should statistics be handled for the metro
42			//Statistics.getInstance().incrementDepartureLookups();
43	torben	1041
44	torben	1042	int station = Integer.parseInt( req.getParameter("station") );
45	torben	1041
46
47	torben	1042	MetroBean bean;
48	torben	1041
49	torben	1042	try {
50	torben	1041
51	torben	1042	bean = fetcher.cachedLookupMetroDepartures(station);
52			String xml = formatXml(bean);
53	torben	1041
54	torben	1042	resp.setDateHeader("Expires", 0);
55			resp.setHeader("Cache-Control", "no-cache, must-revalidate");
56	torben	1060	resp.setContentType("text/xml");
57	torben	1042	resp.getWriter().print(xml);
58	torben	1041
59	torben	1042	} 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	torben	1401	//Statistics.getInstance().incrementDepartureErrors();
72	torben	1042	resp.sendError(500);
73			return;
74	torben	1041	}
75
76
77			}
78
79	torben	1060	String formatXml(MetroBean metro) throws ServletException {
80	torben	1042
81	torben	1060	Serializer serializer = new Persister();
82
83	torben	1190	StringWriter out = new StringWriter();
84	torben	1060
85			try {
86			serializer.write(metro, out);
87			} catch (Exception e) {
88			throw new ServletException(e);
89	torben	1042	}
90
91	torben	1060	return out.toString();
92	torben	1042	}
93
94	torben	1041	}