Class: Nanoc::Core::NotificationCenter

Inherits:
Object
  • Object
show all
Defined in:
lib/nanoc/core/notification_center.rb

Overview

Provides a way to send notifications between objects. It allows blocks associated with a certain notification name to be registered; these blocks will be called when the notification with the given name is posted.

It is a slightly different implementation of the Observer pattern; the table of subscribers is not stored in the observable object itself, but in the notification center.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ NotificationCenter

Returns a new instance of NotificationCenter.



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# File 'lib/nanoc/core/notification_center.rb', line 13

def initialize
  # name => observers dictionary
  @notifications = Hash.new { |hash, name| hash[name] = [] }
end

Class Method Details

.instance ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 35

def instance
  @_instance ||= new
end

.on(name, id = nil) ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 39

def on(name, id = nil, &)
  instance.on(name, id, &)
end

.post(name) ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 43

def post(name, *)
  instance.post(name, *)
end

.remove(name, id) ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 47

def remove(name, id)
  instance.remove(name, id)
end

.reset ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 51

def reset
  @_instance = nil
end

Instance Method Details

#on(name, id = nil, &block) ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 18

def on(name, id = nil, &block)
  @notifications[name] << { id:, block: }
end

#post(name, *args) ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 26

def post(name, *args)
  @notifications[name].each do |observer|
    observer[:block].call(*args)
  end

  self
end

#remove(name, id) ⇒ Object 



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# File 'lib/nanoc/core/notification_center.rb', line 22

def remove(name, id)
  @notifications[name].reject! { |i| i[:id] == id }
end