Java 5.0加入了annotation的特性，算是對Decorator模式有了優雅的支持。現在的JUNIT和Hibernate都有了使用annotation的版本，減輕了代碼的編寫痛苦。但是在Java的GUI領域里面，還沒有使用annotation進行消息處理的例子。我想既然Hibernate可以，那么swing應該也可以，可能是被效率和向下兼容的問題束縛住了。
Python從2.4開始提供了Decorator的支持，其形式和Java大體相當，但本質大相徑庭。
具體的Decorator說明limodou大俠已經說得很清楚了
http://www.donews.net/limodou/archive/2004/12/19/207521.aspx
下面是我沿用Java annotation的思維 寫的一個使用Decorator模式，進行消息處理例子，代碼很不完善，but it works！！！！
msg.py
1 import string, threading
2 from time import sleep, time
3
4
5 def dumpObject(object):
6 print '-'*12
7 print 'Dump',object
8 print '\n'.join([s+' = '+str(getattr(object, s)) for s in dir(object)])
9
10 class MessageSample():
11 def __init__(self,fromObject=None,title='',*args):
12 self.fromObject=fromObject
13 self.title=title
14 self.args=args
15
16 class messageManager():
17
18 object=None
19 @staticmethod
20 def instance():
21 if messageManager.object==None:
22 mutex = threading.Lock()
23 mutex.acquire()
24 if messageManager.object==None:
25 messageManager.object=messageManager()
26 mutex.release()
27 return messageManager.object
28
29 def __init__(self):
30 self.queue=[]
31 self.msgMap={}
32 self.mutex = threading.Lock()
33 self.RunMutex = threading.Lock()
34 self.msgThread=None
35 self.isRun=True
36
37 def push(self,msg):
38 #self.mutex.acquire()
39 self.queue.append(msg)
40 #self.mutex.release()
41
42 def pop(self):
43 #self.mutex.acquire()
44 object = self.queue.pop(0)
45 #self.mutex.release()
46 return object
47
48 def registerMsgHandler(self,fromObject,title,handler):
49 self.mutex.acquire()
50 if self.msgMap.has_key((fromObject,title)):
51 self.msgMap[(fromObject,title)].append(handler)
52 else:
53 self.msgMap[(fromObject,title)]=[handler,]
54 self.mutex.release()
55
56 def removeMsgHandler(self,handler):
57 for k,v in self.msgMap.items():
58 if handler in v:
59 self.mutex.acquire()
60 if handler in v:
61 v.remove(handler)
62 self.mutex.release()
63
64 def processMsg(self,msg):
65 self.mutex.acquire()
66 if (msg.fromObject,msg.title) in self.msgMap:
67 handlers=[handler for handler in self.msgMap[(msg.fromObject,msg.title)] if callable(handler)]
68 #print handlers,msg.args
69 for handler in handlers :
70 handler(*msg.args)
71 self.mutex.release()
72
73 def dumpHandlers(self):
74 for k,v in self.msgMap.items():
75 print k,v
76
77 def run(self):
78
79 self.RunMutex.acquire()
80 self.isRun=True
81 self.RunMutex.release()
82 def threadFunction():
83
84 while self.isRun:
85 try:
86 msg=self.pop()
87 if msg!=None:
88 self.processMsg(msg)
89 except:
90 sleep(0.5)
91
92 self.msgThread=threading.Thread(target=threadFunction)
93 self.msgThread.start()
94
95 def stop(self):
96 if self.msgThread != None:
97 self.RunMutex.acquire()
98 self.isRun=False
99 self.RunMutex.release()
100 def eventHandler(title='',fromObject=None):
101 def wrap(fn):
102 messageManager.instance().registerMsgHandler(fromObject,title,fn)
103 return fn
104 return wrap
105
106 def sendMessage(fromObject,title,*args):
107 msg=MessageSample(fromObject,title,*args)
108 messageManager.instance().push(msg)
1 from msg import *
2 from time import sleep
3 import threading
4
5 @eventHandler('New')
6 def OnNewMsg1(str):
7 print 'Get new message1',str
8
9 @eventHandler('New')
10 def OnNewMsg2(str):
11 print 'Get new message2',str
12
13 @eventHandler('exit')
14 def OnExit():
15
16 messageManager.instance().stop()
17 print 'hello'
18 import sys
19 sys.exit(0)
20
21 class comp():
22 def __init__(self):pass
23 class sample():
24 def __init__(self,str):
25 self.str=str
26 @eventHandler(fromObject=self.str,title='SizeChange')
27 def OnSize(x,y):
28 print 'size',x,y,str
29
30 if __name__=='__main__':
31 #messageManager.instance().dumpHandlers()
32 messageManager.instance().run()
33
34 sendMessage(None,'New','hello')
35 s='I am s'
36 s2='I am s2'
37 S=sample(s)
38 SS=sample(s2)
39 sendMessage(s,'SizeChange',800,600)
40 sendMessage(s2,'SizeChange',800,600)
41 sleep(5)
42 messageManager.instance().removeMsgHandler(OnNewMsg2)
43
44 sendMessage(None,'New','hello')
45
46 messageManager.instance().push(MessageSample(title='exit'))#another way
47
Output：
Get new message1 hello
Get new message2 hello
size 800 600 I am s
size 800 600 I am s2
Get new message1 hello
hello
從代碼可以看出 不用寫什么消息映射表，也不用在代碼中顯示的進行監聽器的注冊，只要在我們寫的消息處理函數上添加元數據就行了
posted on 2008-06-20 15:32
zarra 閱讀(263)
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