-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathApplicationShutdownHooks.java
More file actions
110 lines (96 loc) · 2.69 KB
/
ApplicationShutdownHooks.java
File metadata and controls
110 lines (96 loc) · 2.69 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*/
package java.lang;
import java.util.*;
/*
* Class to track and run user level shutdown hooks registered through
* <tt>{@link Runtime#addShutdownHook Runtime.addShutdownHook}</tt>.
*
* @see java.lang.Runtime#addShutdownHook
* @see java.lang.Runtime#removeShutdownHook
*/
class ApplicationShutdownHooks {
/* The set of registered hooks */
private static IdentityHashMap<Thread, Thread> hooks;
static {
try {
Shutdown.add(1 /* shutdown hook invocation order */,
false /* not registered if shutdown in progress */,
new Runnable() {
public void run() {
runHooks();
}
}
);
hooks = new IdentityHashMap<>();
} catch (IllegalStateException e) {
// application shutdown hooks cannot be added if
// shutdown is in progress.
hooks = null;
}
}
private ApplicationShutdownHooks() {}
/* Add a new shutdown hook. Checks the shutdown state and the hook itself,
* but does not do any security checks.
*/
static synchronized void add(Thread hook) {
if(hooks == null)
throw new IllegalStateException("Shutdown in progress");
if (hook.isAlive())
throw new IllegalArgumentException("Hook already running");
if (hooks.containsKey(hook))
throw new IllegalArgumentException("Hook previously registered");
hooks.put(hook, hook);
}
/* Remove a previously-registered hook. Like the add method, this method
* does not do any security checks.
*/
static synchronized boolean remove(Thread hook) {
if(hooks == null)
throw new IllegalStateException("Shutdown in progress");
if (hook == null)
throw new NullPointerException();
return hooks.remove(hook) != null;
}
/* Iterates over all application hooks creating a new thread for each
* to run in. Hooks are run concurrently and this method waits for
* them to finish.
*/
static void runHooks() {
Collection<Thread> threads;
synchronized(ApplicationShutdownHooks.class) {
threads = hooks.keySet();
hooks = null;
}
for (Thread hook : threads) {
hook.start();
}
for (Thread hook : threads) {
try {
hook.join();
} catch (InterruptedException x) { }
}
}
}