1 /***
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
7 * statements and notices. Redistributions must also contain a
8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Exoffice Technologies. For written permission,
18 * please contact info@exolab.org.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Exoffice Technologies. Exolab is a registered
23 * trademark of Exoffice Technologies.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2000-2005 (C) Exoffice Technologies Inc. All Rights Reserved.
42 *
43 * $Id: BaseLease.java,v 1.2 2005/03/18 03:47:30 tanderson Exp $
44 */
45 package org.exolab.jms.lease;
46
47
48 /***
49 * Generic lease implementation, which may be used to lease any object.
50 *
51 * @author <a href="mailto:jima@comware.com.au">Jim Alateras</a>
52 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
53 * @version $Revision: 1.2 $ $Date: 2005/03/18 03:47:30 $
54 */
55 public class BaseLease
56 implements LeaseIfc, Comparable {
57
58 /***
59 * This is the object that is leased.
60 */
61 protected final Object _leasedObject;
62
63 /***
64 * The duration of the lease in milliseconds.
65 */
66 protected long _duration = 0L;
67
68 /***
69 * This is the time that the lease will expire.
70 */
71 protected long _expiryTime = 0L;
72
73 /***
74 * The listener that will be notified when the lease expires.
75 */
76 protected LeaseEventListenerIfc _listener = null;
77
78
79 /***
80 * Construct a new <code>BaseLease</code>.
81 *
82 * @param object the leased object
83 * @param duration the duration of lease, in milliseconds
84 * @param listener the listener to notify of lease events
85 */
86 public BaseLease(Object object, long duration,
87 LeaseEventListenerIfc listener) {
88 if (object == null) {
89 throw new IllegalArgumentException("Argument 'object' is null");
90 }
91
92 if (listener == null) {
93 throw new IllegalArgumentException("Argument 'listener' is null");
94 }
95
96 _leasedObject = object;
97 _duration = duration;
98 _expiryTime = System.currentTimeMillis() + duration;
99 _listener = listener;
100 }
101
102 /***
103 * Return the absolute expiry time of this lease.
104 *
105 * @return the expiry time of the lease, in milliseconds
106 */
107 public long getExpiryTime() {
108 return _expiryTime;
109 }
110
111 /***
112 * Returns the duration of the lease.
113 *
114 * @return the duration of the lease, in milliseconds
115 */
116 public long getDuration() {
117 return _duration;
118 }
119
120 /***
121 * Change the duration of the lease.
122 *
123 * @param duration the new lease duration, in milliseconds
124 */
125 public void setDuration(long duration) {
126 _duration = duration;
127 _expiryTime = System.currentTimeMillis() + duration;
128 }
129
130 /***
131 * Returns the time remaining on the lease.
132 *
133 * @return the time remaining, in milliseconds
134 */
135 public long getRemainingTime() {
136 return (System.currentTimeMillis() - _expiryTime);
137 }
138
139 /***
140 * Returns the leased object.
141 *
142 * @return the leased object
143 */
144 public Object getLeasedObject() {
145 return _leasedObject;
146 }
147
148 /***
149 * Returns the listener to notify of lease events.
150 *
151 * @return the listener to notify of lease events
152 */
153 public LeaseEventListenerIfc getLeaseEventListener() {
154 return _listener;
155 }
156
157 /***
158 * Compares this object with the specified object. It returns a negative
159 * integer is this object is less than the specified object; zero if this
160 * object is equal to the specified object or a positive integer if this
161 * object is greater than the specified object
162 * <p/>
163 * The comparison is based on the expiration time.
164 */
165 public int compareTo(Object object) {
166 int result = 0;
167
168 if (object instanceof BaseLease) {
169 BaseLease lease = (BaseLease) object;
170 if (lease.getExpiryTime() != this.getExpiryTime()) {
171 if (lease.getExpiryTime() > this.getExpiryTime()) {
172 result = -1;
173 } else {
174 result = 1;
175 }
176 }
177 }
178 return result;
179 }
180
181 /***
182 * Returns a string representation of this object.
183 *
184 * @return a string representation of this
185 */
186 public String toString() {
187 StringBuffer buf = new StringBuffer(_leasedObject.toString());
188 buf.append(" duration = ");
189 buf.append(_duration);
190 buf.append(" expiryTime = ");
191 buf.append(_expiryTime);
192
193 return buf.toString();
194 }
195
196 /***
197 * Notify the listeners that this lease has expird. This method has package
198 * level scope.
199 */
200 protected void notifyLeaseExpired() {
201 synchronized (_listener) {
202 _listener.onLeaseExpired(_leasedObject);
203 }
204 }
205
206 }