thoerup/traininfoservice/LocateStations.java

package dk.thoerup.traininfoservice;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import dk.thoerup.traininfoservice.DBConnection;

/**
 * Servlet implementation class LocateStations
 */
public class LocateStations extends HttpServlet {
        private static final long serialVersionUID = 1L;

        Logger logger = Logger.getLogger( LocateStations.class.toString() );
        
        /**
         * @see HttpServlet#HttpServlet()
         */
        public LocateStations() {
                super();
                // TODO Auto-generated constructor stub
        }

        public enum Requested {
                BY_NAME,
                BY_LOCATION,
                NONE
        }


        protected String getStations(Connection conn, double latitude, double longitude, String name, Requested method) throws SQLException {
                String SQL = "";
                PreparedStatement stmt = null;
                ResultSet res = null;

                StringBuffer buff = new StringBuffer();

                buff.append("<?xml version=\"1.0\" ?>\n");
                buff.append("<stations>\n");    
                
                try
                {

                        switch (method)
                        {
                        case BY_LOCATION:
                                //inner select is workaround from not being able to use a calculated column directly in where clause
                                SQL = "SELECT * FROM ( "+
                                                "               SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog, " + 
                                                "                     earth_distance( ll_to_earth(latitude,longitude), ll_to_earth(?,?))::int AS calcdist " + 
                                                "               FROM trainstations " +
                                                "               WHERE latitude IS NOT NULL AND longitude IS NOT NULL " +
                                                "       ) AS trainstations2 " +
                                                "ORDER BY calcdist ASC " + 
                                                "LIMIT 4 ";
                                stmt = conn.prepareStatement(SQL);
                                stmt.setDouble(1, latitude);
                                stmt.setDouble(2, longitude);

                                break;
                        case BY_NAME:
                                SQL = "SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog,0.0 " + 
                                        "FROM trainstations " + 
                                        "WHERE name ILIKE ? AND latitude IS NOT NULL AND longitude IS NOT NULL " +
                                        "ORDER BY name ";
                                stmt = conn.prepareStatement(SQL);
                                stmt.setString(1, "%" + name + "%");
                                break;
                        default:
                                // This should not be possible
                                logger.severe("getStations(): default switch case");
                        }


                        res = stmt.executeQuery();

                        while (res.next()) {
                                buff.append("<station>\n");

                                buff.append("<id>").append( res.getInt(1) ).append("</id>\n");
                                buff.append("<name>").append( res.getString(2) ) .append("</name>\n");
                                buff.append("<latitude>").append( res.getDouble(3) ) .append("</latitude>\n");
                                buff.append("<longitude>").append( res.getDouble(4) ) .append("</longitude>\n");
                                res.getString(5);
                                buff.append("<fjerntog>").append( !res.wasNull() ) .append("</fjerntog>\n");
                                res.getString(6);
                                buff.append("<stog>").append( !res.wasNull() ) .append("</stog>\n");
                                buff.append("<calcdist>").append( res.getInt(7) ) .append("</calcdist>\n");

                                buff.append("</station>\n");                            
                        }
                } finally {
                        if (res != null && !res.isClosed())
                                res.close();
                        if (stmt != null && !stmt.isClosed())
                                stmt.close();
                }
                buff.append("</stations>\n");
                return buff.toString();
        }

        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

                double longitude = 0.0;
                double latitude = 0.0;
                String name = "";

                Requested method = Requested.NONE;

                if (request.getParameter("latitude") != null && request.getParameter("latitude") != null) { 
                        latitude = Double.parseDouble( request.getParameter("latitude") );
                        longitude = Double.parseDouble( request.getParameter("longitude") );
                        method = Requested.BY_LOCATION;
                }

                if (request.getParameter("name") != null) {
                        name = request.getParameter("name");
                        method = Requested.BY_NAME;
                }


                if (method != Requested.NONE) {

                        Connection conn = null;
                        try {
                                conn = DBConnection.getConnection();

                                String xml = getStations(conn, latitude, longitude, name, method);

                                response.setContentType("text/xml");
                                response.getWriter().print(xml);

                                conn.close();
                                conn = null;
 
                        } catch (Exception e) {                         
                                logger.log(Level.SEVERE, "Exception while finding stations", e);
                                response.sendError(500);                                                
                        } finally {
                                try {
                                        if (conn != null)
                                                conn.close();
                                } catch (Throwable t) {}
                        }
                } else {
                        response.sendError(400, "not enough parameters");
                }
        }

}
1	package dk.thoerup.traininfoservice;
2
3	import java.io.IOException;
4	import java.sql.Connection;
5	import java.sql.PreparedStatement;
6	import java.sql.ResultSet;
7	import java.sql.SQLException;
8	import java.util.logging.Level;
9	import java.util.logging.Logger;
10
11	import javax.servlet.ServletException;
12	import javax.servlet.http.HttpServlet;
13	import javax.servlet.http.HttpServletRequest;
14	import javax.servlet.http.HttpServletResponse;
15
16	import dk.thoerup.traininfoservice.DBConnection;
17
18	/**
19	* Servlet implementation class LocateStations
20	*/
21	public class LocateStations extends HttpServlet {
22	private static final long serialVersionUID = 1L;
23
24	Logger logger = Logger.getLogger( LocateStations.class.toString() );
25
26	/**
27	* @see HttpServlet#HttpServlet()
28	*/
29	public LocateStations() {
30	super();
31	// TODO Auto-generated constructor stub
32	}
33
34	public enum Requested {
35	BY_NAME,
36	BY_LOCATION,
37	NONE
38	}
39
40
41	protected String getStations(Connection conn, double latitude, double longitude, String name, Requested method) throws SQLException {
42	String SQL = "";
43	PreparedStatement stmt = null;
44	ResultSet res = null;
45
46	StringBuffer buff = new StringBuffer();
47
48	buff.append("<?xml version=\"1.0\" ?>\n");
49	buff.append("<stations>\n");
50
51	try
52	{
53
54	switch (method)
55	{
56	case BY_LOCATION:
57	//inner select is workaround from not being able to use a calculated column directly in where clause
58	SQL = "SELECT * FROM ( "+
59	" SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog, " +
60	" earth_distance( ll_to_earth(latitude,longitude), ll_to_earth(?,?))::int AS calcdist " +
61	" FROM trainstations " +
62	" WHERE latitude IS NOT NULL AND longitude IS NOT NULL " +
63	" ) AS trainstations2 " +
64	"ORDER BY calcdist ASC " +
65	"LIMIT 4 ";
66	stmt = conn.prepareStatement(SQL);
67	stmt.setDouble(1, latitude);
68	stmt.setDouble(2, longitude);
69
70	break;
71	case BY_NAME:
72	SQL = "SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog,0.0 " +
73	"FROM trainstations " +
74	"WHERE name ILIKE ? AND latitude IS NOT NULL AND longitude IS NOT NULL " +
75	"ORDER BY name ";
76	stmt = conn.prepareStatement(SQL);
77	stmt.setString(1, "%" + name + "%");
78	break;
79	default:
80	// This should not be possible
81	logger.severe("getStations(): default switch case");
82	}
83
84
85
86
87	res = stmt.executeQuery();
88
89	while (res.next()) {
90	buff.append("<station>\n");
91
92	buff.append("<id>").append( res.getInt(1) ).append("</id>\n");
93	buff.append("<name>").append( res.getString(2) ) .append("</name>\n");
94	buff.append("<latitude>").append( res.getDouble(3) ) .append("</latitude>\n");
95	buff.append("<longitude>").append( res.getDouble(4) ) .append("</longitude>\n");
96	res.getString(5);
97	buff.append("<fjerntog>").append( !res.wasNull() ) .append("</fjerntog>\n");
98	res.getString(6);
99	buff.append("<stog>").append( !res.wasNull() ) .append("</stog>\n");
100	buff.append("<calcdist>").append( res.getInt(7) ) .append("</calcdist>\n");
101
102	buff.append("</station>\n");
103	}
104	} finally {
105	if (res != null && !res.isClosed())
106	res.close();
107	if (stmt != null && !stmt.isClosed())
108	stmt.close();
109	}
110	buff.append("</stations>\n");
111	return buff.toString();
112	}
113
114	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
115
116	double longitude = 0.0;
117	double latitude = 0.0;
118	String name = "";
119
120	Requested method = Requested.NONE;
121
122	if (request.getParameter("latitude") != null && request.getParameter("latitude") != null) {
123	latitude = Double.parseDouble( request.getParameter("latitude") );
124	longitude = Double.parseDouble( request.getParameter("longitude") );
125	method = Requested.BY_LOCATION;
126	}
127
128	if (request.getParameter("name") != null) {
129	name = request.getParameter("name");
130	method = Requested.BY_NAME;
131	}
132
133
134	if (method != Requested.NONE) {
135
136	Connection conn = null;
137	try {
138	conn = DBConnection.getConnection();
139
140	String xml = getStations(conn, latitude, longitude, name, method);
141
142	response.setContentType("text/xml");
143	response.getWriter().print(xml);
144
145	conn.close();
146	conn = null;
147
148	} catch (Exception e) {
149	logger.log(Level.SEVERE, "Exception while finding stations", e);
150	response.sendError(500);
151	} finally {
152	try {
153	if (conn != null)
154	conn.close();
155	} catch (Throwable t) {}
156	}
157	} else {
158	response.sendError(400, "not enough parameters");
159	}
160	}
161
162	}