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Java > Open Source Codes > example > cmp > map > ClientServlet


1 package example.cmp.map;
2
3 import javax.servlet.*;
4 import javax.servlet.http.*;
5
6 import javax.ejb.*;
7
8 import javax.naming.*;
9
10 import java.util.Collection;
11 import java.util.Map;
12 import java.util.Iterator;
13
14 import java.io.PrintWriter;
15
16 /**
17  * A client to illustrate EJB managed identifying relationships and
18  * compound primary keys.
19  */
20 public class ClientServlet extends HttpServlet {
21   StudentHome studentHome = null;
22   CourseHome courseHome = null;
23   GradeHome gradeHome = null;
24
25   /**
26    * Load the EJB Home objects one.
27    */
28   public void init()
29     throws ServletException
30   {
31     try {
32       Context ejb = (Context)new InitialContext().lookup("java:comp/env/cmp");
33
34       // get the Student CMP-Bean home interface
35 studentHome = (StudentHome) ejb.lookup("map_StudentBean");
36       
37       // get the Course CMP-Bean home interface
38 courseHome = (CourseHome) ejb.lookup("map_CourseBean");
39       
40       // get the Grade CMP-Bean home interface
41 gradeHome = (GradeHome) ejb.lookup("map_GradeBean");
42     } catch (NamingException e) {
43       throw new ServletException(e);
44     }
45   }
46
47   /**
48    * Print the statistics for all the students.
49    */
50   public void service(HttpServletRequest req, HttpServletResponse res)
51     throws java.io.IOException, ServletException
52   {
53     res.setContentType("text/html");
54
55     PrintWriter out = res.getWriter();
56
57     // for all students, print their grades.
58 Collection students = null;
59     try {
60       students = studentHome.findAll();
61     } catch(javax.ejb.FinderException e) {
62       throw new ServletException(e);
63     }
64
65     out.println("<title>Student Grades</title>");
66     out.println("<h1>Student Grades</h1>");
67
68     Iterator iter = students.iterator();
69     while (iter.hasNext()) {
70       Student student = (Student) iter.next();
71
72       out.println("<h3>" + student.getName() + "</h3>");
73
74       Map grades = student.getGrades();
75       
76       out.println("<table>");
77       out.println("<tr><th>Course<th>Grade");
78
79       Iterator courseIter = grades.keySet().iterator();
80       while (courseIter.hasNext()) {
81         Course course = (Course) courseIter.next();
82
83         Grade grade = (Grade) grades.get(course);
84
85         out.print("<tr><td>" + course.getName() + "<td>" + grade.getGrade());
86       }
87       out.println("</table>");
88     }
89   }
90 }
91
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