Source Code for Module paramz.core.observable

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 30   
 31   
 32 -class Observable(object): 
 33      """ 
 34      Observable pattern for parameterization. 
 35   
 36      This Object allows for observers to register with self and a (bound!) function 
 37      as an observer. Every time the observable changes, it sends a notification with 
 38      self as only argument to all its observers. 
 39      """ 
 40 -    def __init__(self, *args, **kwargs): 
 41          super(Observable, self).__init__() 
 42          from .lists_and_dicts import ObserverList 
 43          self.observers = ObserverList() 
 44          self._update_on = True 
 45   
 46 -    def set_updates(self, on=True): 
 47          self._update_on = on 
 48   
 49 -    def add_observer(self, observer, callble, priority=0): 
 50          """ 
 51          Add an observer `observer` with the callback `callble` 
 52          and priority `priority` to this observers list. 
 53          """ 
 54          self.observers.add(priority, observer, callble) 
 55   
 56 -    def remove_observer(self, observer, callble=None): 
 57          """ 
 58          Either (if callble is None) remove all callables, 
 59          which were added alongside observer, 
 60          or remove callable `callble` which was added alongside 
 61          the observer `observer`. 
 62          """ 
 63          to_remove = [] 
 64          for poc in self.observers: 
 65              _, obs, clble = poc 
 66              if callble is not None: 
 67                  if (obs is observer) and (callble == clble): 
 68                      to_remove.append(poc) 
 69              else: 
 70                  if obs is observer: 
 71                      to_remove.append(poc) 
 72          for r in to_remove: 
 73              self.observers.remove(*r) 
 74   
 75 -    def notify_observers(self, which=None, min_priority=None): 
 76          """ 
 77          Notifies all observers. Which is the element, which kicked off this 
 78          notification loop. The first argument will be self, the second `which`. 
 79   
 80          .. note:: 
 81              
 82             notifies only observers with priority p > min_priority! 
 83              
 84          :param min_priority: only notify observers with priority > min_priority 
 85                               if min_priority is None, notify all observers in order 
 86          """ 
 87          if self._update_on: 
 88              if which is None: 
 89                  which = self 
 90              if min_priority is None: 
 91                  [callble(self, which=which) for _, _, callble in self.observers] 
 92              else: 
 93                  for p, _, callble in self.observers: 
 94                      if p <= min_priority: 
 95                          break 
 96                      callble(self, which=which) 
 97   
 98 -    def change_priority(self, observer, callble, priority): 
 99          self.remove_observer(observer, callble) 
100          self.add_observer(observer, callble, priority) 
101