class Nanoc::Int::NotificationCenter
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.
@api private
Public Class Methods
Adds the given block to the list of blocks that should be called when the notification with the given name is received.
@param [String, Symbol] name The name of the notification that will
cause the given block to be called.
@param [String, Symbol, nil] id An identifier for the block. This is
only used to be able to remove the block (using the remove method) later. Can be nil, but this is not recommended because it prevents the given notification block from being unregistered.
@yield [*args] Will be executed with the arguments passed to {.post}
@return [void]
# File lib/nanoc/base/services/notification_center.rb, line 27 def on(name, id = nil, &block) initialize_if_necessary(name) # Add observer @notifications[name] << { id: id, block: block } end
Posts a notification with the given name and the given arguments.
@param [String, Symbol] name The name of the notification that should
be posted.
@param args Arguments that wil be passed to the blocks handling the
notification.
@return [void]
# File lib/nanoc/base/services/notification_center.rb, line 43 def post(name, *args) initialize_if_necessary(name) # Notify all observers @notifications[name].each do |observer| observer[:block].call(*args) end end
Removes the block with the given identifier from the list of blocks that should be called when the notification with the given name is posted.
@param [String, Symbol] name The name of the notification that should
no longer be registered.
@param [String, Symbol] id The identifier of the block that should be
removed.
@return [void]
# File lib/nanoc/base/services/notification_center.rb, line 63 def remove(name, id) initialize_if_necessary(name) # Remove relevant observers @notifications[name].reject! { |i| i[:id] == id } end
Private Class Methods
# File lib/nanoc/base/services/notification_center.rb, line 72 def initialize_if_necessary(name) @notifications ||= {} # name => observers dictionary @notifications[name] ||= [] # list of observers end