Source Code for Module AEEvent.StateChange

 1  ''' 
 2  Defines an L{AEEvent} indicating that the state of an accessible or an item 
 3  changed. 
 4   
 5  @author: Peter Parente 
 6  @organization: IBM Corporation 
 7  @copyright: Copyright (c) 2005, 2007 IBM Corporation 
 8  @license: The BSD License 
 9   
10  All rights reserved. This program and the accompanying materials are made  
11  available under the terms of the BSD license which accompanies 
12  this distribution, and is available at 
13  U{http://www.opensource.org/licenses/bsd-license.php} 
14  ''' 
15   
16  import Base 
17   
18 -class StateChange(Base.AccessEngineEvent): 
19    ''' 
20    Event that fires when the state of an accessible or item changes. 
21     
22    This class registers its name and whether it should be monitored by default in 
23    an L{AEMonitor} using the L{Base.registerEventType} function 
24    when this module is first imported. The L{AEMonitor} can use this 
25    information to build its menus. 
26   
27    @ivar name: Name of the property that changed 
28    @type name: string 
29    @ivar value: The new text associated with the property 
30    @type value: string 
31    ''' 
32    Base.registerEventType('StateChange', False) 
33 -  def __init__(self, por, name, value, **kwargs): 
34      ''' 
35      Stores the L{POR}, state name, and its new value. 
36       
37      @param por: Point of regard to the accessible/item whose state changed 
38      @type por: L{POR} 
39      @param name: Name of the state that changed 
40      @type name: string 
41      @param value: New value of the state 
42      @type value: boolean 
43      ''' 
44      Base.AccessEngineEvent.__init__(self, **kwargs) 
45      self.name = name 
46      self.value = value 
47      self.por = por 
48       
49 -  def __str__(self): 
50      ''' 
51      Returns a human readable representation of this event including its name, 
52      its L{POR}, its state name, and its new value. 
53       
54      @return: Information about this event 
55      @rtype: string 
56      ''' 
57      name = Base.AccessEngineEvent.__str__(self) 
58      return '%s:\n\tPOR: %s\n\tstate: %s\n\tvalue: %s' % \ 
59             (name, self.por, self.name, self.value) 
60     
61 -  def execute(self, tier_manager, **kwargs): 
62      ''' 
63      Contacts the L{TierManager} so it can manage the property change event. 
64       
65      @param tier_manager: TierManager that will handle the event 
66      @type tier_manager: L{TierManager} 
67      @param kwargs: Packed references to other managers not of interest here 
68      @type kwargs: dictionary 
69      @return: Always True to indicate the event executed properly 
70      @rtype: boolean 
71      ''' 
72      tier_manager.manageEvent(self) 
73      return True 
74   
75 -  def getDataForTask(self): 
76      '''     
77      Fetches data out of this L{StateChange} for use by a L{Task.StateTask}. 
78       
79      @return: Dictionary of parameters to be passed to a 
80        L{Task.PropertyTask} as follows: 
81          - por:  The L{POR} of the accessible whose property changed 
82          - name: The text name of the property that changed 
83          - value: The new value of the state (True or False) 
84      @rtype: dictionary 
85      ''' 
86      return {'por':self.getPOR(), 'name':self.name, 'value':self.value} 
87