Source Code for Module flumotion.component.base.statewatcher

 1  # -*- Mode: Python; test-case-name: flumotion.test.test_feedcomponent010 -*- 
 2  # vi:si:et:sw=4:sts=4:ts=4 
 3  # 
 4  # Flumotion - a streaming media server 
 5  # Copyright (C) 2004,2005,2006,2007,2008 Fluendo, S.L. (www.fluendo.com). 
 6  # All rights reserved. 
 7   
 8  # This file may be distributed and/or modified under the terms of 
 9  # the GNU General Public License version 2 as published by 
10  # the Free Software Foundation. 
11  # This file is distributed without any warranty; without even the implied 
12  # warranty of merchantability or fitness for a particular purpose. 
13  # See "LICENSE.GPL" in the source distribution for more information. 
14   
15  # Licensees having purchased or holding a valid Flumotion Advanced 
16  # Streaming Server license may use this file in accordance with the 
17  # Flumotion Advanced Streaming Server Commercial License Agreement. 
18  # See "LICENSE.Flumotion" in the source distribution for more information. 
19   
20  # Headers in this file shall remain intact. 
21   
22  # this class is a bit of an experiment 
23  # editor's note: "experiment" is an excuse for undocumented and uncommented 
24 -class StateWatcher(object): 
25 -    def __init__(self, state, setters, appenders, removers, 
26              setitemers=None, delitemers=None): 
27          self.state = state 
28          self.setters = setters 
29          self.appenders = appenders 
30          self.removers = removers 
31          self.setitemers = setitemers 
32          self.delitemers = delitemers 
33          self.shown = False 
34   
35          state.addListener(self, set_=self.onSet, append=self.onAppend, 
36                            remove=self.onRemove, setitem=self.onSetItem, 
37                            delitem=self.onDelItem) 
38   
39          for k in appenders: 
40              for v in state.get(k): 
41                  self.onAppend(state, k, v) 
42   
43 -    def hide(self): 
44          if self.shown: 
45              for k in self.setters: 
46                  self.onSet(self.state, k, None) 
47              self.shown = False 
48   
49 -    def show(self): 
50          # "show" the watcher by triggering all the registered setters 
51          if not self.shown: 
52              self.shown = True 
53              for k in self.setters: 
54                  self.onSet(self.state, k, self.state.get(k)) 
55   
56 -    def onSet(self, obj, k, v): 
57          if self.shown and k in self.setters: 
58              self.setters[k](self.state, v) 
59   
60 -    def onAppend(self, obj, k, v): 
61          if k in self.appenders: 
62              self.appenders[k](self.state, v) 
63   
64 -    def onRemove(self, obj, k, v): 
65          if k in self.removers: 
66              self.removers[k](self.state, v) 
67   
68 -    def onSetItem(self, obj, k, sk, v): 
69          if self.shown and k in self.setitemers: 
70              self.setitemers[k](self.state, sk, v) 
71   
72 -    def onDelItem(self, obj, k, sk, v): 
73          if self.shown and k in self.setitemers: 
74              self.setitemers[k](self.state, sk, v) 
75   
76 -    def unwatch(self): 
77          if self.state: 
78              self.hide() 
79              for k in self.removers: 
80                  for v in self.state.get(k): 
81                      self.onRemove(self.state, k, v) 
82              self.state.removeListener(self) 
83              self.state = None 
84