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comparison src/org/dancres/blitz/notify/EventGenerator.java @ 0:3dc0c5604566

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Initial checkin of blitz 2.0 fcs - no installer yet.
author Dan Creswell <dan.creswell@gmail.com>
date Sat, 21 Mar 2009 11:00:06 +0000
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1 package org.dancres.blitz.notify;
2
3 import net.jini.space.JavaSpace;
4
5 import org.dancres.blitz.txn.TxnId;
6
7 import org.dancres.blitz.mangler.MangledEntry;
8
9 import org.dancres.blitz.oid.OID;
10
11 /**
12 <p> Represents a single registration via notify. If it's transactional,
13 it will never be saved as it's considered temporary. If it's transactional
14 it will be saved to disk. In addition, it's state will be saved to the
15 log periodically (on a number of allocations basis) to preserve data
16 in case of a crash. <p>
17
18 <p> This class uses notifyPreparer to do initial preparation of the
19 passed RemoteEventListener when constructed from scratch (i.e. it's a new
20 registration). It uses recoveredNotifyPreparer in those cases where it
21 has been de-serialized from storage and is about to be used for the first
22 time post a restart </p>
23
24 <p> Instances of this object can be "tainted" for various reasons including
25 certain kinds of exception from the remote notify implementation, lease
26 expiry or transaction commit. Tainting prevents any further operations
27 against this instance such as event dispatch, logging changes to disk and
28 lease renewal. Tainting also results in cleanup for the registration being
29 scheduled.</p>
30 */
31 public interface EventGenerator {
32 public void assign(OID anOID);
33
34 public long getStartSeqNum();
35
36 public OID getId();
37
38 public boolean isPersistent();
39
40 public long getSourceId();
41
42 /**
43 Once an EventGenerator becomes tainted it will generate no more events
44 and schedule cleanup.
45 */
46 public void taint();
47
48 /* ********************************************************************
49 Event filtering starts here
50 **********************************************************************/
51
52 /**
53 Determines whether the passed QueueEvent is "visible" to this
54 EventGenerator. This is determind by checking transaction id's, expiry
55 and that the generator isn't "tainted"
56 */
57 public boolean canSee(QueueEvent anEvent, long aTime);
58
59 /**
60 * @return a handback to use in the send event or null indicating no match
61 */
62 public boolean matches(MangledEntry anEntry);
63
64 /* ********************************************************************
65 Lease management starts here
66 **********************************************************************/
67
68 public boolean renew(long aTime);
69
70 /* ********************************************************************
71 Recovery starts here
72 **********************************************************************/
73
74 public void recover(long aSeqNum);
75
76 /**
77 Jumps the sequence number by the RESTART_JUMP
78 */
79 public long jumpSequenceNumber();
80
81 /**
82 Jumps the sequence number if it's not already at this minimum.
83 */
84 public long jumpSequenceNumber(long aMin);
85
86
87 /* ********************************************************************
88 Event Generation starts here
89 **********************************************************************/
90
91 /**
92 Dispatches a remote event to a client using the passed source.
93 */
94 public void ping(QueueEvent anEvent, JavaSpace aSource);
95
96 /* ********************************************************************
97 State save/recovery starts here
98 **********************************************************************/
99
100 public EventGeneratorState getMemento();
101 }