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1
27
28 package storagebin;
29
30 import java.sql.*;
31 import javax.sql.*;
32 import java.util.*;
33 import javax.ejb.*;
34 import javax.naming.*;
35
36
37 public class WidgetBean implements EntityBean, WidgetRemoteBusiness {
38 private String  widgetId;
39 private String description;
40 private double price;
41 private EntityContext context;
42 private Connection con;
43 private String dbName = "jdbc/pointbase";
44
45 public String getDescription() {
46 return description;
47 }
48
49 public double getPrice() {
50 return price;
51 }
52
53 public String ejbCreate(String widgetId, String description, double price)
54 throws CreateException {
55 try {
56 insertRow(widgetId, description, price);
57 } catch (Exception ex) {
58 throw new EJBException("ejbCreate: " + ex.getMessage());
59 }
60
61 this.widgetId = widgetId;
62 this.description = description;
63 this.price = price;
64
65 return widgetId;
66 }
67
68 public String ejbFindByPrimaryKey(String primaryKey)
69 throws FinderException {
70 boolean result;
71
72 try {
73 result = selectByPrimaryKey(primaryKey);
74 } catch (Exception ex) {
75 throw new EJBException("ejbFindByPrimaryKey: " + ex.getMessage());
76 }
77
78 if (result) {
79 return primaryKey;
80 } else {
81 throw new ObjectNotFoundException("Row for id " + primaryKey +
82 " not found.");
83 }
84 }
85
86 public void ejbRemove() {
87 try {
88 deleteRow(widgetId);
89 } catch (Exception ex) {
90 throw new EJBException("ejbRemove: " + ex.getMessage());
91 }
92 }
93
94 public void setEntityContext(EntityContext context) {
95 this.context = context;
96 }
97
98 public void unsetEntityContext() {
99 }
100
101 public void ejbActivate() {
102 widgetId = (String ) context.getPrimaryKey();
103 }
104
105 public void ejbPassivate() {
106 widgetId = null;
107 }
108
109 public void ejbLoad() {
110 try {
111 loadRow();
112 } catch (Exception ex) {
113 throw new EJBException("ejbLoad: " + ex.getMessage());
114 }
115 }
116
117 public void ejbStore() {
118 try {
119 storeRow();
120 } catch (Exception ex) {
121 throw new EJBException("ejbLoad: " + ex.getMessage());
122 }
123 }
124
125 public void ejbPostCreate(String widgetId, String description, double price) {
126 }
127
128
129 private void makeConnection() {
130 try {
131 InitialContext ic = new InitialContext();
132 DataSource ds = (DataSource) ic.lookup(dbName);
133
134 con = ds.getConnection();
135 } catch (Exception ex) {
136 throw new EJBException("Unable to connect to database. " +
137 ex.getMessage());
138 }
139 }
140
141 private void releaseConnection() {
142 try {
143 con.close();
144 } catch (SQLException ex) {
145 throw new EJBException("releaseConnection: " + ex.getMessage());
146 }
147 }
148
149 private void insertRow(String widgetId, String description, double price)
150 throws SQLException {
151 makeConnection();
152
153 String insertStatement = "insert into widget values ( ? , ? , ? )";
154 PreparedStatement prepStmt = con.prepareStatement(insertStatement);
155
156 prepStmt.setString(1, widgetId);
157 prepStmt.setString(2, description);
158 prepStmt.setDouble(3, price);
159
160 prepStmt.executeUpdate();
161 prepStmt.close();
162 releaseConnection();
163 }
164
165 private void deleteRow(String widgetId) throws SQLException {
166 makeConnection();
167
168 String deleteStatement = "delete from widget where widgetid = ? ";
169 PreparedStatement prepStmt = con.prepareStatement(deleteStatement);
170
171 prepStmt.setString(1, widgetId);
172 prepStmt.executeUpdate();
173 prepStmt.close();
174 releaseConnection();
175 }
176
177 private boolean selectByPrimaryKey(String primaryKey)
178 throws SQLException {
179 makeConnection();
180
181 String selectStatement =
182 "select widgetid " + "from widget where widgetid = ? ";
183 PreparedStatement prepStmt = con.prepareStatement(selectStatement);
184
185 prepStmt.setString(1, primaryKey);
186
187 ResultSet rs = prepStmt.executeQuery();
188 boolean result = rs.next();
189
190 prepStmt.close();
191 releaseConnection();
192
193 return result;
194 }
195
196 private void loadRow() throws SQLException {
197 makeConnection();
198
199 String selectStatement =
200 "select description, price " + "from widget where widgetid = ? ";
201 PreparedStatement prepStmt = con.prepareStatement(selectStatement);
202
203 prepStmt.setString(1, this.widgetId);
204
205 ResultSet rs = prepStmt.executeQuery();
206
207 if (rs.next()) {
208 this.description = rs.getString(1);
209 this.price = rs.getDouble(2);
210 prepStmt.close();
211 } else {
212 prepStmt.close();
213 throw new NoSuchEntityException("Row for widgetId " + widgetId +
214 " not found in database.");
215 }
216
217 releaseConnection();
218 }
219
220 private void storeRow() throws SQLException {
221 makeConnection();
222
223 String updateStatement =
224 "update widget set description = ? , " + "price = ? " +
225 "where widgetid = ?";
226 PreparedStatement prepStmt = con.prepareStatement(updateStatement);
227
228 prepStmt.setString(1, description);
229 prepStmt.setDouble(2, price);
230 prepStmt.setString(3, widgetId);
231
232 int rowCount = prepStmt.executeUpdate();
233
234 prepStmt.close();
235
236 if (rowCount == 0) {
237 throw new EJBException("Storing row for widgetId " + widgetId +
238 " failed.");
239 }
240
241 releaseConnection();
242 }
243 }
244
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