1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package net.jini.lookup;
20
21 import net.jini.core.lease.Lease;
22
23 /**
24 * Data structure used to group together the lease and event sequence
25 * number. For each LookupCache, there is a HashMap that maps a ProxyReg to
26 * an EventReg.
27 *
28 * EventReg's object lock is also used to maintain atomicity of
29 * lookup service state.
30 */
31 final class EventReg {
32 /* The Event source from the event registration */
33 final Object source;
34 /* The Event ID */
35 final long eventID;
36 /* The current event sequence number for the Service template */
37 private long seqNo;
38 /* The Event notification lease */
39 final Lease lease;
40 /* Event Suspension */
41 boolean suspended;
42 /* Discarded Registrar */
43 boolean discarded;
44
45 EventReg(Object source, long eventID, long seqNo, Lease lease) {
46 this.source = source;
47 this.eventID = eventID;
48 this.seqNo = seqNo;
49 this.lease = lease;
50 }
51
52 /**
53 * @param seqNo the seqNo to set, return a positive delta if successful,
54 * otherwise a negative value indicates failure.
55 */
56 long updateSeqNo(long seqNo) {
57 assert Thread.holdsLock(this);
58 long difference;
59 difference = seqNo - this.seqNo;
60 if (difference > 0) {
61 this.seqNo = seqNo;
62 return difference;
63 } else {
64 return difference; // Return a negative or zero value
65 }
66 }
67
68 boolean nonContiguousEvent(long seqNo){
69 assert Thread.holdsLock(this);
70 long difference = seqNo - this.seqNo;
71 this.notifyAll();
72 return difference != 1;
73 }
74
75 void suspendEvents() {
76 suspended = true;
77 }
78
79 boolean eventsSuspended(){
80 return suspended;
81 }
82
83 void releaseEvents() {
84 suspended = false;
85 }
86
87 boolean discard() {
88 if (discarded) return false;
89 discarded = true;
90 return true;
91 }
92
93 boolean discarded(){
94 return discarded;
95 }
96
97 } //end class ServiceDiscoveryManager.EventReg