A Ruby Gem to register and trigger events. It is based on Vienna::Emittable. It is thread safe.

gem install emittable

First require 'emittable' in your project. Then you can include Emittable in your classes. If you override initialize remember to call super.

require 'emittable'

class A
  include Emittable
  
  def initialize(...)
    super
    ...
  end
  
  ...
  ...
  
end

a = A.new(...)

To register a new event callback call on on an instance of your class, passing the name of the event and a block as the callback. You can add as many callbacks as you want for an event.

a.on(:shutdown) do
  ...
end

a.on(:shutdown) do
  ...
  ...
end

To trigger all the event's callbacks call trigger, passing the name of the event.

a.trigger(:shutdown)

You can also pass arguments to trigger that will get passed to a callback block.

a.on(:shutdown) do |a, b|
  ...
end

a.trigger(:shutdown, 1, 2)

To remove a callback you must have already saved a reference to the callback block. You can then call off, passing the block.

callback = proc { ... }

a.on(:shutdown, &callback)

a.off(:shutdown, callback)