class Concurrent::Collection::CopyOnNotifyObserverSet

@api private
prevent concurrency issues
a notification is required the internal data structure is copied to
observers are added and removed from a thread safe collection; every time
A thread safe observer set implemented using copy-on-read approach:

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

@!macro observable_add_observer 
def add_observer(observer = nil, func = :update, &block)
  if observer.nil? && block.nil?
    raise ArgumentError, 'should pass observer as a first argument or block'
  elsif observer && block
    raise ArgumentError.new('cannot provide both an observer and a block')
  end
  if block
    observer = block
    func     = :call
  end
  synchronize do
    @observers[observer] = func
    observer
  end
end

def count_observers

@!macro observable_count_observers 
def count_observers
  synchronize { @observers.count }
end

def delete_observer(observer)

@!macro observable_delete_observer 
def delete_observer(observer)
  synchronize do
    @observers.delete(observer)
    observer
  end
end

def delete_observers

@!macro observable_delete_observers 
def delete_observers
  synchronize do
    @observers.clear
    self
  end
end

def duplicate_and_clear_observers 

def duplicate_and_clear_observers
  synchronize do
    observers = @observers.dup
    @observers.clear
    observers
  end
end

def duplicate_observers 

def duplicate_observers
  synchronize { @observers.dup }
end

def initialize 

def initialize
  super()
  synchronize { ns_initialize }
end

def notify_and_delete_observers(*args, &block)

Returns:
  • (CopyOnWriteObserverSet) - self

Parameters:
  • args (Object) -- arguments to be passed to each observer 
def notify_and_delete_observers(*args, &block)
  observers = duplicate_and_clear_observers
  notify_to(observers, *args, &block)
  self
end

def notify_observers(*args, &block)

Returns:
  • (CopyOnWriteObserverSet) - self

Parameters:
  • args (Object) -- arguments to be passed to each observer 
def notify_observers(*args, &block)
  observers = duplicate_observers
  notify_to(observers, *args, &block)
  self
end

def notify_to(observers, *args) 

def notify_to(observers, *args)
  raise ArgumentError.new('cannot give arguments and a block') if block_given? && !args.empty?
  observers.each do |observer, function|
    args = yield if block_given?
    observer.send(function, *args)
  end
end

def ns_initialize 

def ns_initialize
  @observers = {}
end