KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > example > cmp > basic > Course


1 package example.cmp.basic;
2
3 import javax.ejb.*;
4
5 /**
6  * Local interface for a course taught at Hogwarts, providing
7  * methods to view and change it.
8  *
9  * <code><pre>
10  * CREATE TABLE basic_courses (
11  * course_id VARCHAR(250) NOT NULL,
12  * teacher VARCHAR(250),
13  *
14  * PRIMARY KEY(course_id)
15  * );
16  * </pre></code>
17  *
18  * <p>All Course instances are obtained from the CourseHome interface, and
19  * all access to the Course table occurs through the Course interface.
20  * Clients can never use the CourseBean implementation directly or directly
21  * access the database for the course table. Because Resin-CMP has
22  * complete control over the database's course entries, it can more
23  * effectively cache results, often avoiding slow database access.
24  *
25  * <p>CourseId is the bean's primary key. Every entity bean must have
26  * a primary key.
27  *
28  * There is a <code>setInstructor</code> mutator, but no
29  * <code>setCourseId</code> mutator because clients can't set the primary key.
30  * Resin-CMP needs to implement the <code>
31  * setCourseId</code> method that has been defined in the implementation
32  * class,<code>CourseBean.java</code>. But the Implementation Class is
33  * not associated with any particular entities -- it is only used by the
34  * container to implement the Local Interface. If you want to use a method from
35  * the implementation class when calling from a client, it has to be made
36  * available explicitly in the Local Interface.
37  *
38  */
39 public interface Course extends EJBLocalObject {
40   /**
41    * Returns the ID of the course (CMP field). This is also the primary
42    * key as defined in ejb-jar.xml. There's no corresponding setCourseId
43    * method in the local interface because clients must not change the
44    * primary key.
45    */
46   public String getId();
47
48   /**
49    * Returns the instructor's name (CMP field). More sophisticated
50    * applications will create a separate entity bean for the instructor
51    * instead of using a string. The more sophisticated application will
52    * use a relationship field to manage the instructor for a course.
53    *
54    * @see example.cmp.one2one
55    */
56   public String getInstructor();
57
58   /**
59    * Sets the instructor's name (CMP field).
60    *
61    * @param instructor the name of the new instructor.
62    */
63   public void setInstructor(String instructor);
64   
65   /**
66    * Swaps the instructor for a course. This business method will run in
67    * a transaction, like all business methods in an entity bean.
68    * The transaction protects the database from inconsistency when
69    * several clients try to modify the database simultaneously.
70    *
71    * @param course the course which will swap instructors.
72    */
73   public void swap(Course course);
74 }
75
Popular Tags