|
1
8
9 package foxtrot.pumps;
10
11 import java.lang.reflect.Method  ;
12 import java.lang.reflect.InvocationHandler ;
13 import java.lang.reflect.Proxy ;
14 import java.lang.reflect.InvocationTargetException ;
15 import java.security.AccessController ;
16 import java.security.PrivilegedExceptionAction ;
17 import java.security.PrivilegedAction ;
18 import java.awt.AWTEvent ;
19 import java.awt.EventQueue ;
20 import java.awt.Toolkit ;
21
22 import foxtrot.EventPump;
23 import foxtrot.Task;
24
25
31 public class ConditionalEventPump implements EventPump, EventFilterable
32 {
33 private static Class conditionalClass;
34 private static Method pumpEventsMethod;
35 static final boolean debug = false;
36
37 static
38 {
39 try
40 {
41 AccessController.doPrivileged(new PrivilegedExceptionAction ()
42 {
43 public Object run() throws ClassNotFoundException , NoSuchMethodException
44 {
45 ClassLoader loader = ClassLoader.getSystemClassLoader();
46 conditionalClass = loader.loadClass("java.awt.Conditional");
47 Class dispatchThreadClass = loader.loadClass("java.awt.EventDispatchThread");
48 pumpEventsMethod = dispatchThreadClass.getDeclaredMethod("pumpEvents", new Class []{conditionalClass});
49 pumpEventsMethod.setAccessible(true);
50
51 String property = "sun.awt.exception.handler";
53 String handler = System.getProperty(property);
54 if (handler == null)
55 {
56 handler = ThrowableHandler.class.getName();
57 System.setProperty(property, handler);
58 if (debug) System.out.println("[ConditionalEventPump] Installing AWT Throwable Handler " + handler);
59 }
60 else
61 {
62 if (debug) System.out.println("[ConditionalEventPump] Using already installed AWT Throwable Handler " + handler);
63 }
64 return null;
65 }
66 });
67 }
68 catch (Throwable x)
69 {
70 if (debug) x.printStackTrace();
71 throw new Error (x.toString());
72 }
73 }
74
75 private EventFilter filter;
76
77 public void setEventFilter(EventFilter filter)
78 {
79 this.filter = filter;
80 }
81
82 public EventFilter getEventFilter()
83 {
84 return filter;
85 }
86
87 public void pumpEvents(Task task)
88 {
89 if (task == null) return;
91
92 try
93 {
94 if (debug) System.out.println("[ConditionalEventPump] Start pumping events - Pump is " + this + " - Task is " + task);
95
96 Object conditional = Proxy.newProxyInstance(conditionalClass.getClassLoader(), new Class []{conditionalClass}, new Conditional(task));
98 pumpEventsMethod.invoke(Thread.currentThread(), new Object []{conditional});
99 }
100 catch (InvocationTargetException x)
101 {
102 Throwable t = x.getTargetException();
105 System.err.println("[ConditionalEventPump] Exception occurred during event dispatching:");
106 t.printStackTrace();
107
108 if (t instanceof RuntimeException )
111 throw (RuntimeException )t;
112 else
113 throw (Error )t;
114 }
115 catch (Throwable x)
116 {
117 System.err.println("[ConditionalEventPump] PANIC: uncaught exception in Foxtrot code");
119 x.printStackTrace();
120 }
121 finally
122 {
123 waitForTask(task);
127
128 if (debug) System.out.println("[ConditionalEventPump] Stop pumping events - Pump is " + this + " - Task is " + task);
129 }
130 }
131
132 private void waitForTask(Task task)
133 {
134 try
135 {
136 synchronized (task)
137 {
138 while (!task.isCompleted())
139 {
140 if (debug) System.out.println("[ConditionalEventPump] Waiting for Task " + task + " to complete (GUI freeze)");
141 task.wait();
142 }
143 if (debug) System.out.println("[ConditionalEventPump] Task " + task + " is completed");
144 }
145 }
146 catch (InterruptedException x)
147 {
148 Thread.currentThread().interrupt();
150 }
151 }
152
153
159 private Boolean pumpEvent(Task task)
160 {
161 Boolean completed = task.isCompleted() ? Boolean.TRUE : Boolean.FALSE;
162 if (completed.booleanValue()) return Boolean.FALSE;
164
165 while (true)
166 {
167 AWTEvent nextEvent = waitForEvent();
169 if (nextEvent == null) return Boolean.FALSE;
170 if (debug) System.out.println("[ConditionalEventPump] Next Event: " + nextEvent);
171
172 if (!canPumpEvent(nextEvent)) return Boolean.FALSE;
175
176 if (filter == null || filter.accept(nextEvent)) return Boolean.TRUE;
178
179 nextEvent = getNextEvent();
182 if (nextEvent == null) return Boolean.FALSE;
183 if (debug) System.out.println("[ConditionalEventPump] Filtered out AWT Event: " + nextEvent + " by filter " + filter);
184 }
185 }
186
187
199 protected boolean canPumpEvent(AWTEvent event)
200 {
201 return true;
202 }
203
204 private EventQueue getEventQueue()
205 {
206 return (EventQueue )AccessController.doPrivileged(new PrivilegedAction ()
207 {
208 public Object run()
209 {
210 return Toolkit.getDefaultToolkit().getSystemEventQueue();
211 }
212 });
213 }
214
215 private AWTEvent getNextEvent()
216 {
217 try
218 {
219 return getEventQueue().getNextEvent();
220 }
221 catch (InterruptedException x)
222 {
223 Thread.currentThread().interrupt();
224 return null;
225 }
226 }
227
228
235 private AWTEvent waitForEvent()
236 {
237 EventQueue queue = getEventQueue();
238 AWTEvent nextEvent = null;
239 synchronized (queue)
240 {
241 while ((nextEvent = peekEvent(queue)) == null)
242 {
243 if (debug) System.out.println("[ConditionalEventPump] Waiting for events...");
244 try
245 {
246 queue.wait();
247 }
248 catch (InterruptedException x)
249 {
250 Thread.currentThread().interrupt();
251 return null;
252 }
253 }
254 }
255 return nextEvent;
256 }
257
258
261 protected AWTEvent peekEvent(EventQueue queue)
262 {
263 return queue.peekEvent();
264 }
265
266
270 private class Conditional implements InvocationHandler
271 {
272 private final Task task;
273
274
277 private Conditional(Task task)
278 {
279 this.task = task;
280 }
281
282
285 public Object invoke(Object proxy, Method method, Object [] args) throws Throwable
286 {
287 return pumpEvent(task);
288 }
289 }
290
291
300 public static class ThrowableHandler
301 {
302
307 public void handle(Throwable t)
308 {
309 System.err.println("[ConditionalEventPump] Exception occurred during event dispatching:");
310 t.printStackTrace();
311 }
312 }
313 }
314 |
Popular Tags |
Java API By Example, From Geeks To Geeks.