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1
27
28 package enroller;
29
30 import java.sql.*;
31 import javax.sql.*;
32 import java.util.*;
33 import javax.ejb.*;
34 import javax.naming.*;
35 import javax.rmi.PortableRemoteObject  ;
36
37
38 public class StudentBean implements EntityBean, StudentRemoteBusiness {
39 private static final String dbName = "jdbc/pointbase";
40 private String studentId;
41 private String name;
42 private ArrayList courseIds;
43 private Connection con;
44 private EntityContext context;
45 private EnrollerRemoteHome enrollerHome;
46
47 public ArrayList getCourseIds() {
48 System.out.println("in getCourseIds");
49
50 return courseIds;
51 }
52
53 public String getName() {
54 return name;
55 }
56
57 public void setName(String name) {
58 this.name = name;
59 }
60
61 public String ejbCreate(String studentId, String name)
62 throws CreateException {
63 System.out.println("in ejbCreate");
64
65 try {
66 insertStudent(studentId, name);
67 } catch (Exception ex) {
68 throw new EJBException("ejbCreate: " + ex.getMessage());
69 }
70
71 this.studentId = studentId;
72 this.name = name;
73 System.out.println("about to leave ejbCreate");
74
75 return studentId;
76 }
77
78 public String ejbFindByPrimaryKey(String primaryKey)
79 throws FinderException {
80 boolean result;
81
82 try {
83 result = selectByPrimaryKey(primaryKey);
84 } catch (Exception ex) {
85 throw new EJBException("ejbFindByPrimaryKey: " + ex.getMessage());
86 }
87
88 if (result) {
89 return primaryKey;
90 } else {
91 throw new ObjectNotFoundException("Row for id " + primaryKey +
92 " not found.");
93 }
94 }
95
96 public void ejbRemove() {
97 try {
98 deleteStudent(studentId);
99 } catch (Exception ex) {
100 throw new EJBException("ejbRemove: " + ex.getMessage());
101 }
102 }
103
104 public void setEntityContext(EntityContext context) {
105 System.out.println("in setEntityContext");
106 this.context = context;
107 courseIds = new ArrayList();
108
109 try {
110
111 enrollerHome = lookupEnrollerBean();
112 } catch (Exception ex) {
113 throw new EJBException("setEntityContext: " + ex.getMessage());
114 }
115 }
116
117 public void unsetEntityContext() {
118 }
119
120 public void ejbActivate() {
121 studentId = (String ) context.getPrimaryKey();
122 }
123
124 public void ejbPassivate() {
125 studentId = null;
126 }
127
128 public void ejbLoad() {
129 System.out.println("in ejbLoad");
130
131 try {
132 loadStudent();
133 loadCourseIds();
134 } catch (Exception ex) {
135 throw new EJBException("ejbLoad: " + ex.getMessage());
136 }
137
138 System.out.println("leaving ejbLoad");
139 }
140
141 private void loadCourseIds() {
142 System.out.println("in loadCourseIds");
143 courseIds.clear();
144 System.out.println("in loadCourseIds, about to try");
145
146 try {
147 EnrollerRemote enroller = enrollerHome.create();
148 ArrayList a = enroller.getCourseIds(studentId);
149
150 courseIds.addAll(a);
151 } catch (Exception ex) {
152 throw new EJBException("Exception in loadCourseIds: " +
153 ex.getMessage());
154 }
155
156 System.out.println("leaving loadCourseIds");
157 }
158
159 public void ejbStore() {
160 System.out.println("in ejbStore");
161
162 try {
163 storeStudent();
164 } catch (Exception ex) {
165 throw new EJBException("ejbStore: " + ex.getMessage());
166 }
167
168 System.out.println("leaving ejbStore");
169 }
170
171 public void ejbPostCreate(String studentId, String name) {
172 }
173
174
175 private void makeConnection() {
176 try {
177 InitialContext ic = new InitialContext();
178 DataSource ds = (DataSource) ic.lookup(dbName);
179
180 con = ds.getConnection();
181 } catch (Exception ex) {
182 throw new EJBException("Unable to connect to database. " +
183 ex.getMessage());
184 }
185 }
186
187 private void releaseConnection() {
188 try {
189 con.close();
190 } catch (SQLException ex) {
191 throw new EJBException("releaseConnection: " + ex.getMessage());
192 }
193 }
194
195 private void insertStudent(String studentId, String name)
196 throws SQLException {
197 makeConnection();
198
199 String insertStatement = "insert into student values ( ? , ? )";
200 PreparedStatement prepStmt = con.prepareStatement(insertStatement);
201
202 prepStmt.setString(1, studentId);
203 prepStmt.setString(2, name);
204
205 prepStmt.executeUpdate();
206 prepStmt.close();
207 releaseConnection();
208 }
209
210 private boolean selectByPrimaryKey(String primaryKey)
211 throws SQLException {
212 makeConnection();
213
214 String selectStatement =
215 "select studentid " + "from student where studentid = ? ";
216 PreparedStatement prepStmt = con.prepareStatement(selectStatement);
217
218 prepStmt.setString(1, primaryKey);
219
220 ResultSet rs = prepStmt.executeQuery();
221 boolean result = rs.next();
222
223 prepStmt.close();
224 releaseConnection();
225
226 return result;
227 }
228
229 private void deleteStudent(String studentId) throws SQLException {
230 makeConnection();
231
232 String deleteStatement =
233 "delete from student " + "where studentid = ?";
234 PreparedStatement prepStmt = con.prepareStatement(deleteStatement);
235
236 prepStmt.setString(1, studentId);
237 prepStmt.executeUpdate();
238 prepStmt.close();
239 releaseConnection();
240 }
241
242 private void loadStudent() throws SQLException {
243 makeConnection();
244
245 String selectStatement =
246 "select name " + "from student where studentid = ? ";
247 PreparedStatement prepStmt = con.prepareStatement(selectStatement);
248
249 prepStmt.setString(1, studentId);
250
251 ResultSet rs = prepStmt.executeQuery();
252
253 if (rs.next()) {
254 name = rs.getString(1);
255 prepStmt.close();
256 } else {
257 prepStmt.close();
258 throw new NoSuchEntityException("Row for studentId " + studentId +
259 " not found in database.");
260 }
261
262 releaseConnection();
263 }
264
265 private void storeStudent() throws SQLException {
266 makeConnection();
267
268 String updateStatement =
269 "update student set name = ? " + "where studentid = ?";
270 PreparedStatement prepStmt = con.prepareStatement(updateStatement);
271
272 prepStmt.setString(1, name);
273 prepStmt.setString(2, studentId);
274
275 int rowCount = prepStmt.executeUpdate();
276
277 prepStmt.close();
278
279 if (rowCount == 0) {
280 throw new EJBException("Storing row for studentId " + studentId +
281 " failed.");
282 }
283
284 releaseConnection();
285 }
286
287 private enroller.EnrollerRemoteHome lookupEnrollerBean() {
288 try {
289 javax.naming.Context c = new javax.naming.InitialContext ();
290 Object remote = c.lookup("ejb/SimpleEnroller");
291 enroller.EnrollerRemoteHome rv = (enroller.EnrollerRemoteHome) javax.rmi.PortableRemoteObject.narrow(remote, enroller.EnrollerRemoteHome.class);
292 return rv;
293 }
294 catch(javax.naming.NamingException ne) {
295 java.util.logging.Logger.getLogger(getClass().getName()).log(java.util.logging.Level.SEVERE,"exception caught" ,ne);
296 throw new RuntimeException (ne);
297 }
298
299 }
300 }
301 |
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