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1
9 package com.vladium.util.exit;
10
11 import java.util.HashMap  ;
12 import java.util.Map ;
13
14 import sun.misc.Signal;
15 import sun.misc.SignalHandler;
16
17 import com.vladium.util.IJREVersion;
18 import com.vladium.util.Property;
19 import com.vladium.emma.IAppConstants;
20
21
25 public
26 abstract class ExitHookManager implements IJREVersion
27 {
28
30
32 public abstract boolean addExitHook (Runnable runnable);
33 public abstract boolean removeExitHook (Runnable runnable);
34
35 public static synchronized ExitHookManager getSingleton ()
36 {
37 if (s_singleton == null)
38 {
39 if (JRE_1_3_PLUS)
40 {
41 s_singleton = new JRE13ExitHookManager ();
42 }
43 else if (JRE_SUN_SIGNAL_COMPATIBLE)
44 {
45 s_singleton = new SunJREExitHookManager ();
46 }
47 else
48 {
49 throw new UnsupportedOperationException ("no shutdown hook manager available [JVM: " + Property.getSystemFingerprint () + "]");
50 }
51 }
52
53 return s_singleton;
54 }
55
56
58
59 protected ExitHookManager () {}
60
61
63
65
66 private static final class JRE13ExitHookManager extends ExitHookManager
67 {
68 public synchronized boolean addExitHook (final Runnable runnable)
69 {
70 if ((runnable != null) && ! m_exitThreadMap.containsKey (runnable))
71 {
72 final Thread exitThread = new Thread (runnable, IAppConstants.APP_NAME + " shutdown handler thread");
73
74 try
75 {
76 Runtime.getRuntime ().addShutdownHook (exitThread);
77 m_exitThreadMap.put (runnable, exitThread);
79 return true;
80 }
81 catch (Exception e)
82 {
83 System.out.println ("exception caught while adding a shutdown hook:");
84 e.printStackTrace (System.out);
85 }
86 }
87
88 return false;
89 }
90
91 public synchronized boolean removeExitHook (final Runnable runnable)
92 {
93 if (runnable != null)
94 {
95 final Thread exitThread = (Thread ) m_exitThreadMap.get (runnable);
97 if (exitThread != null)
98 {
99 try
100 {
101 Runtime.getRuntime ().removeShutdownHook (exitThread);
102 m_exitThreadMap.remove (runnable);
103
104 return true;
105 }
106 catch (Exception e)
107 {
108 System.out.println ("exception caught while removing a shutdown hook:");
109 e.printStackTrace (System.out);
110 }
111 }
112 }
113
114 return false;
115 }
116
117 JRE13ExitHookManager ()
118 {
119 m_exitThreadMap = new HashMap ();
120 }
121
122
123 private final Map m_exitThreadMap;
124
125 }
127
128 private static final class SunJREExitHookManager extends ExitHookManager
129 {
130 public synchronized boolean addExitHook (final Runnable runnable)
131 {
132 if ((runnable != null) && ! m_signalHandlerMap.containsKey (runnable))
133 {
134 final INTSignalHandler handler = new INTSignalHandler (runnable);
135
136 try
137 {
138 handler.register ();
139 m_signalHandlerMap.put (runnable, handler);
141 return true;
142 }
143 catch (Throwable t)
144 {
145 System.out.println ("exception caught while adding a shutdown hook:");
146 t.printStackTrace (System.out);
147 }
148 }
149
150 return false;
151 }
152
153 public synchronized boolean removeExitHook (final Runnable runnable)
154 {
155 if (runnable != null)
156 {
157 final INTSignalHandler handler = (INTSignalHandler) m_signalHandlerMap.get (runnable); if (handler != null)
159 {
160 try
161 {
162 handler.unregister ();
163 m_signalHandlerMap.remove (runnable);
164
165 return true;
166 }
167 catch (Exception e)
168 {
169 System.out.println ("exception caught while removing a shutdown hook:");
170 e.printStackTrace (System.out);
171 }
172 }
173 }
174
175 return false;
176 }
177
178 SunJREExitHookManager ()
179 {
180 m_signalHandlerMap = new HashMap ();
181 }
182
183
184 private final Map m_signalHandlerMap;
185
186 }
188
189 private static final class INTSignalHandler implements SignalHandler
190 {
191 public synchronized void handle (final Signal signal)
192 {
193 if (m_runnable != null)
194 {
195 try
196 {
197 m_runnable.run ();
198 }
199 catch (Throwable ignore) {}
200 }
201 m_runnable = null;
202
203 if ((m_previous != null) && (m_previous != SIG_DFL) && (m_previous != SIG_IGN))
204 {
205 try
206 {
207
211 m_previous.handle (signal);
212 }
213 catch (Throwable ignore) {}
214 }
215 else
216 {
217 System.exit (0);
218 }
219 }
220
221 INTSignalHandler (final Runnable runnable)
222 {
223 m_runnable = runnable;
224 }
225
226 synchronized void register ()
227 {
228 m_previous = Signal.handle (new Signal ("INT"), this);
229 }
230
231 synchronized void unregister ()
232 {
233
239 m_runnable = null;
240 }
241
242
243 private Runnable m_runnable;
244 private SignalHandler m_previous;
245
246 }
248
249 private static ExitHookManager s_singleton;
250
251 } |
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