Contents

module Commute

  # Internal: A Simple EventEmitter modelled after node.js' EventEmitter.
  # More info: http://nodejs.org/api/events.html
  #
  # Include this module in any model that wants to send events to its listeners.
  #
  # Listen to events using `on(:event)`. In the model, notify listeners
  # by calling `emit(:event, ...)` with some arguments.
  module EventEmitter

    # Internal: Initializes an empty handler hash.
    def initialize *args
      super *args
      @handlers = Hash.new { |h, k| h[k] = [] }
    end

    # Internal: Subscribe a handler to an event.
    #
    # event   - The name of the event to listen for.
    # handler - The proc to call when this event occurs.
    #
    # Returns Nothing.
    def on event, &handler
      @handlers[event] << handler
      nil
    end

    # Internal: Subscribe a handler to an event and
    # unsuscribe it when the event fired once.
    #
    def once event, &handler
      on event do |*args, &block|
        handler.call *args, &block
        remove event, handler
      end
    end

    # Internal: Remove an event handler.
    def remove event, handler
      @handlers[event].delete handler
    end

    protected

    # Internal: Emit an event to all handlers.
    #
    # event - The name of the event.
    # args  - Arguments to send to the listeners.
    #
    # Returns the notified handlers.
    def emit event, *args
      @handlers[event].each do |handler|
        handler.call *args
      end
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
commute-0.3.0.pre.2	lib/commute/core/util/event_emitter.rb
commute-0.3.0.pre	lib/commute/core/util/event_emitter.rb