/[projects]/android/TrainInfoService/src/dk/thoerup/traininfoservice/StationDAO.java
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Annotation of /android/TrainInfoService/src/dk/thoerup/traininfoservice/StationDAO.java

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Revision 737 - (hide annotations) (download)
Wed May 19 07:40:00 2010 UTC (14 years ago) by torben
File size: 5277 byte(s)
limit the number of distance calculations by only calculating on those stations within 2.5 degrees (lat/long)-range 
on current server this reduces query time by ~45 ms
1 torben 588 package dk.thoerup.traininfoservice;
2    
3     import java.sql.Connection;
4     import java.sql.PreparedStatement;
5     import java.sql.ResultSet;
6     import java.sql.SQLException;
7     import java.sql.Statement;
8     import java.util.ArrayList;
9     import java.util.List;
10    
11     public class StationDAO {
12     private StationBean convertSingleRow(ResultSet res) throws SQLException {
13     StationBean station = new StationBean();
14    
15     station.setId( res.getInt(1) );
16     station.setName( res.getString(2) );
17     station.setLatitude( res.getDouble(3) );
18     station.setLongitude( res.getDouble(4) );
19     station.setRegional( res.getString(5) );
20     station.setStrain( res.getString(6) );
21     station.setMetro( res.getString(7) );
22     station.setAddress( res.getString(8) );
23     station.setCalcdist( (int)res.getDouble(9) );
24    
25     return station;
26     }
27    
28     private List<StationBean> convertResultset(ResultSet res) throws SQLException {
29     List<StationBean> stations = new ArrayList<StationBean>();
30     while (res.next()) {
31     stations.add( convertSingleRow(res) );
32     }
33     return stations;
34    
35     }
36    
37    
38     public StationBean getById(int id) throws SQLException {
39     String SQL = "SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog,stationcode_metro,address,0.0 " +
40     "FROM trainstations WHERE id=" + id + " AND enabled=true";
41    
42     Connection conn = null;
43 torben 589 Statement stmt = null;
44     ResultSet res = null;
45 torben 588 StationBean result;
46    
47     try {
48     conn = DBConnection.getConnection();
49    
50 torben 589 stmt = conn.createStatement();
51     res = stmt.executeQuery(SQL);
52 torben 588 res.next();
53     result = convertSingleRow(res);
54     } finally {
55 torben 589 if (res != null)
56     res.close();
57     if (stmt != null)
58     stmt.close();
59 torben 588 if (conn != null)
60     conn.close();
61     }
62    
63     return result;
64     }
65    
66 torben 714 /*
67     * this code requires theses statements are run on database in order to do ILIKE searches against aliases (which is defines as array of varchar(64) )
68     * create function rlike(text,text) returns bool as
69     * 'select $2 ilike $1' language sql strict immutable;
70     * create operator ~~~ (procedure = rlike, leftarg = text, rightarg = text, commutator = ~~);
71     */
72 torben 588 public List<StationBean> getByName(String name) throws SQLException {
73     String SQL = "SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog, stationcode_metro, address, 0.0 " +
74     "FROM trainstations " +
75 torben 714 "WHERE (name ILIKE ? OR ? ~~~ ANY(aliases)) AND enabled = true " +
76 torben 588 "ORDER BY name ";
77    
78    
79     List<StationBean> result;
80     Connection conn = null;
81 torben 589 PreparedStatement stmt = null;
82     ResultSet res = null;
83 torben 588 try {
84     conn = DBConnection.getConnection();
85 torben 589 stmt = conn.prepareStatement(SQL);
86 torben 588
87     stmt.setString(1, name + "%");
88 torben 714 stmt.setString(2, name + "%");
89 torben 588
90 torben 589 res = stmt.executeQuery();
91     result = convertResultset(res);
92 torben 588
93     } finally {
94 torben 589 if (res != null)
95     res.close();
96     if (stmt != null)
97     stmt.close();
98     if (conn!= null)
99 torben 588 conn.close();
100     }
101     return result;
102     }
103    
104 torben 737 //the "hack" with max 2.5 degrees latitude and longitude is only valid since we only service danish trains
105 torben 588 public List<StationBean> getByLocation(double latitude, double longitude) throws SQLException {
106 torben 734 String SQL = "SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog, stationcode_metro, address," +
107     " earth_distance( earth_coord, ll_to_earth(?,?))::int AS calcdist " +
108     "FROM trainstations " +
109 torben 737 "WHERE enabled = true AND abs(latitude-?)<2.5 AND abs (longitude-?)<2.5 " +
110 torben 734 "ORDER BY calcdist ASC " +
111     "LIMIT 4 ";
112 torben 588 List<StationBean> result;
113     Connection conn = null;
114 torben 589 PreparedStatement stmt = null;
115     ResultSet res = null;
116 torben 588 try {
117     conn = DBConnection.getConnection();
118 torben 589 stmt = conn.prepareStatement(SQL);
119 torben 588 stmt.setDouble(1, latitude);
120     stmt.setDouble(2, longitude);
121 torben 737 stmt.setDouble(3, latitude);
122     stmt.setDouble(4, longitude);
123 torben 589 res = stmt.executeQuery();
124     result = convertResultset(res);
125 torben 588
126     } finally {
127 torben 589 if (res != null)
128     res.close();
129     if (stmt != null)
130     stmt.close();
131     if (conn!= null)
132 torben 588 conn.close();
133     }
134     return result;
135     }
136    
137     public List<StationBean> getByList(String list) throws SQLException {
138     String SQL = "SELECT id,name,latitude,longitude,stationcode_fjrn,stationcode_stog,stationcode_metro, address,0.0 " +
139     "FROM trainstations " +
140     "WHERE id IN " + list + " AND enabled = true " +
141     "ORDER BY name ";
142    
143     Connection conn = null;
144 torben 589 Statement stmt = null;
145     ResultSet res = null;
146 torben 588 List<StationBean> result;
147    
148     try {
149     conn = DBConnection.getConnection();
150 torben 589 stmt = conn.createStatement();
151     res = stmt.executeQuery(SQL);
152 torben 588 result = convertResultset(res);
153     } finally {
154 torben 589 if (res != null)
155     res.close();
156     if (stmt != null)
157     stmt.close();
158 torben 588 if (conn!= null)
159     conn.close();
160     }
161    
162     return result;
163    
164     }
165 torben 650 public static String getStationName(int stationID) {
166     String station = "";
167    
168     Connection conn = null;
169     try {
170     conn = DBConnection.getConnection();
171     Statement stmt = conn.createStatement();
172     ResultSet rs = stmt.executeQuery("SELECT name FROM trainstations WHERE id=" + stationID);
173     if (rs.next()) {
174     station = rs.getString(1);
175     }
176    
177     } catch (Exception e) {
178     } finally {
179     try {
180     if (conn != null && !conn.isClosed())
181     conn.close();
182     } catch (Exception e) {}
183     }
184    
185     return station;
186     }
187 torben 588 }

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