class Concurrent::IVar

def add_observer(observer = nil, func = :update, &block)

Parameters:
  • func (Symbol) -- symbol naming the method to call when this `Observable` has changes`
  • observer (Object) -- the object that will be notified of changes 
def add_observer(observer = nil, func = :update, &block)
  raise ArgumentError.new('cannot provide both an observer and a block') if observer && block
  direct_notification = false
  if block
    observer = block
    func = :call
  end
  mutex.synchronize do
    if event.set?
      direct_notification = true
    else
      observers.add_observer(observer, func)
    end
  end
  observer.send(func, Time.now, self.value, reason) if direct_notification
  observer
end