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	torben	1041	package dk.thoerup.traininfoservice.banedk;
2
3			import java.io.IOException;
4	torben	1042	import java.util.logging.Level;
5	torben	1041	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	torben	1042	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	torben	1041
18
19	torben	1042
20	torben	1041	@WebServlet(urlPatterns={"/MetroServlet"})
21			public class MetroServlet extends HttpServlet {
22	torben	1042
23			private static final long serialVersionUID = 1L;
24
25			Logger logger = Logger.getLogger(MetroServlet.class.getName());
26	torben	1041
27	torben	1042	MetroFetcher fetcher = new MetroFetcher();
28	torben	1041
29	torben	1042	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
30	torben	1041
31	torben	1042	if (req.getParameter("station") == null) {
32			resp.sendError(400, "not enough parameters");
33			return;
34			}
35	torben	1041
36	torben	1042	//TODO: How should statistics be handled for the metro
37			//Statistics.getInstance().incrementDepartureLookups();
38	torben	1041
39	torben	1042	int station = Integer.parseInt( req.getParameter("station") );
40	torben	1041
41
42	torben	1042	MetroBean bean;
43	torben	1041
44	torben	1042	try {
45	torben	1041
46	torben	1042	bean = fetcher.cachedLookupMetroDepartures(station);
47			String xml = formatXml(bean);
48	torben	1041
49	torben	1042	resp.setDateHeader("Expires", 0);
50			resp.setHeader("Cache-Control", "no-cache, must-revalidate");
51			resp.getWriter().print(xml);
52	torben	1041
53	torben	1042	} 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	torben	1041	}
69
70
71			}
72
73	torben	1042	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	torben	1056	sb.append(" <minutes>" + entry.minutes + "</minutes>\n");
86	torben	1042	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	torben	1041	}