Source Code for Module Task.CyclicInputTask

 1  ''' 
 2  Defines a L{Task} to execute a sequence of  a L{AEEvent.InputGesture} occurs. 
 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 InputTask, Base 
15   
16 -class CyclicInputTask(InputTask.InputTask): 
17    ''' 
18    Executes when an input gesture occurs. In turn, this task will execute the  
19    next named L{Task.InputTask}s stored in this object. 
20     
21    Unlike other L{Task} classes, this one is unlikely to be subclassed. The 
22    common use is to instantiate it directly with names of other input tasks 
23    and bind it to an input command. 
24     
25    This class registers its name and whether it should be monitored by default 
26    in an L{AEMonitor} using the L{Base.registerTaskType} function when this 
27    module is first imported. The L{AEMonitor} can use this information to build 
28    its menus. 
29    ''' 
30    Base.registerTaskType('CyclicInputTask', False) 
31     
32 -  def __init__(self, ident, *names): 
33      ''' 
34      Stores a sequence of named L{InputTask}s to execute. 
35       
36      @param ident: Programmatic identifier 
37      @type ident: string 
38      @param names: Names of L{Task}s that should be executed 
39      @type names: list of string 
40      ''' 
41      InputTask.InputTask.__init__(self, ident) 
42      self.names = names 
43       
44 -  def execute(self, cycle_count, layer, **kwargs): 
45      ''' 
46      Executes the next named L{Task} in the cycle in response to an input  
47      gesture. Called by L{Tier.Tier._executeTask}. 
48       
49      @param cycle_count: Task index in sequence to execute 
50      @type cycle_count: integer 
51      @param layer: Layer on which the event occurred, ignored here but pulled  
52        out of kwargs so kwargs can be passed directly to L{doTask} 
53      @type layer: integer 
54      @param kwargs: Dictionary containing parameters passed to a task. 
55      @type kwargs: dictionary  
56      @return: Should processing continue? Defaults to the return value from the 
57        invoked L{Task}. 
58      @rtype: boolean 
59      ''' 
60      if not len(self.names): 
61        # do nothing if no tasks to cycle 
62        return 
63      i = cycle_count % len(self.names) 
64      return self.doTask(self.names[i], **kwargs) 
65     
66 -  def update(self, cycle_count, layer, **kwargs): 
67      ''' 
68      Executes the next named L{Task} in the cycle in response to an input  
69      gesture. Called by L{Tier.Tier._executeTask}. 
70       
71      @param cycle_count: Task index in sequence to execute 
72      @type cycle_count: integer 
73      @param layer: Layer on which the event occurred, ignored here but pulled  
74        out of kwargs so kwargs can be passed directly to L{doTask} 
75      @type layer: integer 
76      @param kwargs: Dictionary containing parameters passed to a task. 
77      @type kwargs: dictionary  
78      @return: Should processing continue? Defaults to the return value from the 
79        invoked L{Task}. 
80      @rtype: boolean 
81      ''' 
82      if not len(self.names): 
83        # do nothing if no tasks to cycle 
84        return 
85      i = cycle_count % len(self.names) 
86      return self.doTask(self.names[i], propagate=False, **kwargs) 
87