xref: /illumos-gate/usr/src/cmd/pools/poold/com/sun/solaris/service/timer/SimpleRecurringEventTimer.java (revision 55fea89dcaa64928bed4327112404dcb3e07b79f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  *
26  * ident	"%Z%%M%	%I%	%E% SMI"
27  */
28 
29 package com.sun.solaris.service.timer;
30 
31 /**
32  * A recurring event timer.  Like all Java time consumers, which rely on
33  * wall time, adjustments to the time of day will adversely affect the
34  * accuracy of the period.
35  */
36 public class SimpleRecurringEventTimer implements RecurringEventTimer
37 {
38 	/**
39 	 * Next time the event is to occur.
40 	 */
41 	private long nextFiring;
42 
43 	/**
44 	 * Period between recurrences of the event, in milliseconds.
45 	 */
46 	private long period;
47 
48 	/**
49 	 * Multiplier to convert seconds to milliseconds.
50 	 */
51 	public static final int SEC = 1000;
52 
53 	/**
54 	 * Establishes a timer which will fire every 'period'
55 	 * milliseconds starting from now.
56 	 */
SimpleRecurringEventTimer(long period)57 	public SimpleRecurringEventTimer(long period)
58 	{
59 		this.period = period;
60 		nextFiring = System.currentTimeMillis() + period;
61 	}
62 
63 	/**
64 	 * Cause the current thread to wait until at least the time of
65 	 * the next event, as near as possible, unless interrupted.
66 	 *
67 	 * @throws InterruptedException if the thread is interrupted
68 	 * while waiting for the next firing.  Subsequent calls to this
69 	 * method will wait for the same firing.
70 	 */
waitUntilNextFiring()71 	public void waitUntilNextFiring() throws InterruptedException
72 	{
73 		long delta;
74 
75 		while ((delta = nextFiring - System.currentTimeMillis()) > 0)
76 			Thread.sleep(delta);
77 
78 		nextFiring += period;
79 	}
80 }
81