Source Code for Module AEEvent.FocusChange

  1  ''' 
  2  Defines an L{AEEvent} indicating that the focus has changed. 
  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   
 15  import Base 
 16  from AEConstants import LAYER_FOCUS 
 17   
 18 -class FocusChange(Base.AccessEngineEvent): 
 19    ''' 
 20    Event that fires when the focused accessible 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 gained: Type of focus change: True if gained, False if lost 
 28    @type gained: boolean 
 29    ''' 
 30    Base.registerEventType('FocusChange', True) 
 31     
 32 -  def __init__(self, por, gained, **kwargs): 
 33      ''' 
 34      Stores the L{POR} for the focused object and the type of focus event. 
 35       
 36      @param por: Point-of-regard from the accessible that just got focus 
 37      @type por: L{POR} 
 38      @param gained: Was focused gained or lost? 
 39      @type gained: boolean 
 40      ''' 
 41      Base.AccessEngineEvent.__init__(self, **kwargs) 
 42      self.por = por 
 43      self.gained = gained 
 44       
 45 -  def __str__(self): 
 46      ''' 
 47      Returns a human readable representation of this event including its name, 
 48      its L{POR}, and its type. 
 49       
 50      @return: Information about this event 
 51      @rtype: string 
 52      ''' 
 53      name = Base.AccessEngineEvent.__str__(self) 
 54      if self.gained: 
 55        action = 'gained' 
 56      else: 
 57        action = 'lost' 
 58      return '%s:\n\tPOR: %s\n\taction: %s' % (name, self.por, action) 
 59       
 60 -  def getFocusPOR(self): 
 61      ''' 
 62      Returns the L{POR} for this focus event. Used by L{Tier} to maintain a  
 63      focus L{POR}. 
 64       
 65      @return: Point-of-regard for this focus event 
 66      @rtype: L{POR} 
 67      ''' 
 68      return self.por 
 69     
 70 -  def getDataForTask(self): 
 71      ''' 
 72      Fetches data out of this L{FocusChange} for use by a 
 73      L{Task.FocusTask}. 
 74       
 75      @return: Dictionary of parameters to be passed to a L{Task.FocusTask} 
 76        as follows: 
 77          - por:  The L{POR} of the accessible in which the focus change occured 
 78          - type: Whether focus was gained (True) or lost (False) 
 79      @rtype: dictionary 
 80      ''' 
 81      return {'por' : self.getPOR(), 'gained' : self.gained} 
 82       
 83 -  def execute(self, tier_manager, view_manager, **kwargs): 
 84      ''' 
 85      Contacts the L{TierManager} so it can manage the focus change event. 
 86       
 87      @param tier_manager: TierManager that will handle the event 
 88      @type tier_manager: L{TierManager} 
 89      @param kwargs: Packed references to other managers not of interest here 
 90      @type kwargs: dictionary 
 91      @return: True if there is an active view, False if not to delay execution  
 92        of this event until there is 
 93      @rtype: boolean 
 94      ''' 
 95      if view_manager.getAEView() is None and self.layer == LAYER_FOCUS: 
 96        return False 
 97      else: 
 98        tier_manager.manageEvent(self) 
 99        return True 
100