1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22 package javax.jdo;
23
24 /*** A <code>PersistenceCapable</code> class that provides callback methods for life
25 * cycle events implements this interface.
26 *
27 * <P>For JDO 2.0, <code>InstanceCallbacks</code> has been refactored to extend
28 * four other interfaces, without changing any of the methods or semantics.
29 * This allows fine-grained control over callbacks, for
30 * example to allow a class to implement the load callback without
31 * implementing any of the other callbacks. For backward compatibility
32 * with JDO 1.0, the <code>InstanceCallbacks</code> interface is preserved.
33 *
34 * <P>Classes which include non-persistent fields whose values depend
35 * on the values of persistent fields require callbacks on specific
36 * JDO instance life cycle events in order to correctly populate the
37 * values in these fields.
38 *
39 * <P>The callbacks might also be used if the persistent instances
40 * need to be put into the runtime infrastructure of the application.
41 * For example, a persistent instance might notify other instances
42 * on changes to state. The persistent instance might be in a list of
43 * managed instances. When the persistent instance is made hollow,
44 * it can no longer generate change events, and the persistent
45 * instance should be removed from the list of managed instances.
46 *
47 * <P>To implement this, the application programmer would implement
48 * <code>jdoPostLoad</code> to put itself into the list of managed
49 * instances, and implement <code>jdoPreClear</code> to remove itself from
50 * the list. With JDO 1.0, the domain class would be declared to implement
51 * <code>InstanceCallbacks</code>. With JDO 2.0, the domain class
52 * would be declared to implement
53 * <code>javax.jdo.listener.LoadCallback</code> and
54 * <code>javax.jdo.listener.ClearCallback</code>.
55 *
56 * <P>Note that JDO does not manage the state of non-persistent
57 * fields, and when a JDO instance transitions to hollow, JDO clears
58 * the persistent fields. It is the programmer's responsibility to
59 * clear non-persistent fields so that garbage collection of
60 * referred instances can occur.
61 *
62 * @since 1.0
63 * @version 2.0
64 */
65 public interface InstanceCallbacks
66 extends javax.jdo.listener.ClearCallback,
67 javax.jdo.listener.DeleteCallback,
68 javax.jdo.listener.LoadCallback,
69 javax.jdo.listener.StoreCallback {
70 }