Source Code for Module Task.EventTask

 1  ''' 
 2  Defines the base class for all L{Task}s. 
 3   
 4  @author: Peter Parente 
 5  @organization: IBM Corporation 
 6  @copyright: Copyright (c) 2005, 2007 IBM Corporation 
 7  @license: The BSD License 
 8   
 9  All rights reserved. This program and the accompanying materials are made  
10  available under the terms of the BSD license which accompanies 
11  this distribution, and is available at 
12  U{http://www.opensource.org/licenses/bsd-license.php} 
13  ''' 
14  import Base 
15   
16 -class EventTask(Base.Task): 
17    ''' 
18    Base class for all L{Task}s that execute in response to L{AEEvent}s. 
19     
20    The focus, tier, and background parameters specify on which layer 
21    the L{Task} will handle events. If focus is True, the L{Task} will be 
22    executed in response to an event from a focused control within this L{Tier}. 
23    If tier is True, the L{Task} will be executed in response to an event from an 
24    unfocused control within this L{Tier}. If background is True, the L{Task} 
25    will be executed in response to an event from any control within the tier 
26    when the L{Tier} is not active. 
27       
28    The three layers are mutually exclusive. You may set any combination of 
29    focus, tier, and background to True to register the given L{Task} on each 
30    selected layer in one call. If all three parameters are False, the 
31    registration defaults to the focus layer. 
32     
33    @ivar layers: Execute on focused events, unfocused events when the L{Tier}  
34    is active, and/or events when the L{Tier} is inactive? 
35    @type layers: 3-tuple of boolean 
36    '''  
37 -  def __init__(self, ident, focus=False, tier=False, background=False,  
38                 all=False): 
39      ''' 
40      Stores layer information. 
41       
42      @param ident: Programmatic identifier 
43      @type ident: string 
44      @param focus: Execute for events in focus? 
45      @type focus: boolean 
46      @param tier: Execute for unfocused events when the L{Tier} is active? 
47      @type tier: boolean 
48      @param background: Execute for events when the L{Tier} is inactive? 
49      @type background: boolean 
50      ''' 
51      Base.Task.__init__(self, ident) 
52      if all: 
53        self.layers = (True, True, True) 
54      else: 
55        self.layers = (focus, tier, background) 
56       
57 -  def getEventType(self): 
58      ''' 
59      @return: Type of event this L{Task} wants to handle 
60      @rtype: L{AEEvent} class 
61      @raise NotImplementedError: When a subclass does not define the type of  
62        L{AEEvent} it wants to handle 
63      ''' 
64      raise NotImplementedError 
65     
66 -  def getEventLayers(self): 
67      ''' 
68      @return: Event layer information 
69      @rtype: 3-tuple of boolean 
70      ''' 
71      return self.layers 
72