traininfoservice/banedk/MetroServlet.java

package dk.thoerup.traininfoservice.banedk;

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 dk.thoerup.circuitbreaker.CircuitBreakerException;
import dk.thoerup.traininfoservice.Statistics;
import dk.thoerup.traininfoservice.banedk.MetroFetcher.MetroBean;
import dk.thoerup.traininfoservice.banedk.MetroFetcher.MetroEntry;


@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.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) {
                StringBuilder sb = new StringBuilder();
                
                sb.append("<metrodepatures>\n");
                sb.append(" <head>" + metro.head + "</head>\n");
                sb.append(" <operations>" + metro.operationInfo + "</operations>\n");
                
                sb.append(" <entries>\n");
                for (MetroEntry entry : metro.entries) {
                        sb.append("  <entry>\n");
                        sb.append("   <metro>" + entry.metro + "</metro>\n");
                        sb.append("   <destination>" + entry.destination + "</destination>\n");
                        sb.append("   <minutes>" + entry.minutes + "</minutes>\n");
                        sb.append("  </entry>\n");
                }
                sb.append(" </entries>\n");
                
                sb.append(" <plan>" + metro.plan + "</plan>\n");
                
                sb.append("</metrodepatures>\n");
                
                
                return sb.toString();
        }
        
}
1	package dk.thoerup.traininfoservice.banedk;
2
3	import java.io.IOException;
4	import java.util.logging.Level;
5	import java.util.logging.Logger;
6
7	import javax.servlet.ServletException;
8	import javax.servlet.annotation.WebServlet;
9	import javax.servlet.http.HttpServlet;
10	import javax.servlet.http.HttpServletRequest;
11	import javax.servlet.http.HttpServletResponse;
12
13	import dk.thoerup.circuitbreaker.CircuitBreakerException;
14	import dk.thoerup.traininfoservice.Statistics;
15	import dk.thoerup.traininfoservice.banedk.MetroFetcher.MetroBean;
16	import dk.thoerup.traininfoservice.banedk.MetroFetcher.MetroEntry;
17
18
19
20	@WebServlet(urlPatterns={"/MetroServlet"})
21	public class MetroServlet extends HttpServlet {
22
23	private static final long serialVersionUID = 1L;
24
25	Logger logger = Logger.getLogger(MetroServlet.class.getName());
26
27	MetroFetcher fetcher = new MetroFetcher();
28
29	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
30
31	if (req.getParameter("station") == null) {
32	resp.sendError(400, "not enough parameters");
33	return;
34	}
35
36	//TODO: How should statistics be handled for the metro
37	//Statistics.getInstance().incrementDepartureLookups();
38
39	int station = Integer.parseInt( req.getParameter("station") );
40
41
42	MetroBean bean;
43
44	try {
45
46	bean = fetcher.cachedLookupMetroDepartures(station);
47	String xml = formatXml(bean);
48
49	resp.setDateHeader("Expires", 0);
50	resp.setHeader("Cache-Control", "no-cache, must-revalidate");
51	resp.getWriter().print(xml);
52
53	} catch (java.io.IOException ioe) {
54	logger.warning("Metro read failed, station="+station + ". " + ioe.getMessage() );
55	//Statistics.getInstance().incrementDepartureErrors();
56	resp.sendError(500);
57	return;
58	} catch (CircuitBreakerException cbe) {
59	logger.warning("Circuitbreaker - failing fast");
60	//Statistics.getInstance().incrementDepartureErrors();
61	resp.sendError(500);
62	return;
63	} catch (Exception e) {
64	logger.log(Level.WARNING, "Unknown exception, metro-station=" +station, e);
65	Statistics.getInstance().incrementDepartureErrors();
66	resp.sendError(500);
67	return;
68	}
69
70
71	}
72
73	String formatXml(MetroBean metro) {
74	StringBuilder sb = new StringBuilder();
75
76	sb.append("<metrodepatures>\n");
77	sb.append(" <head>" + metro.head + "</head>\n");
78	sb.append(" <operations>" + metro.operationInfo + "</operations>\n");
79
80	sb.append(" <entries>\n");
81	for (MetroEntry entry : metro.entries) {
82	sb.append(" <entry>\n");
83	sb.append(" <metro>" + entry.metro + "</metro>\n");
84	sb.append(" <destination>" + entry.destination + "</destination>\n");
85	sb.append(" <minutes>" + entry.minutes + "</minutes>\n");
86	sb.append(" </entry>\n");
87	}
88	sb.append(" </entries>\n");
89
90	sb.append(" <plan>" + metro.plan + "</plan>\n");
91
92	sb.append("</metrodepatures>\n");
93
94
95	return sb.toString();
96	}
97
98	}