Module: Sentinel::ClassMethods

Defined in:
lib/sentinel.rb

Instance Method Summary collapse

Instance Method Details

#observe(class_name, method_name, options = {}) ⇒ Object



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# File 'lib/sentinel.rb', line 9

def observe(class_name, method_name, options = {})
  sentinel = self

  options = {
    :method_to_notify => :notify,
    :intercept => :after
  }.merge(options)

  if options[:intercept] == :before
    calls = <<-CODE
      sentinel.send("#{options[:method_to_notify]}", observer_opt, *args)
      self.send("#{method_name}_without_observer", *args)
    CODE
  else
    calls = <<-CODE
      result = self.send("#{method_name}_without_observer", *args)
      observer_opt[:result] = result
      sentinel.send("#{options[:method_to_notify]}", observer_opt, *args)
      result
    CODE
  end

  body = <<-CODE
    define_method "#{method_name}_with_observer" do |*args|
      observer_opt = {:subject => self}
      #{calls}
    end

    alias_method "#{method_name}_without_observer", method_name
    alias_method method_name, "#{method_name}_with_observer"
  CODE

  if options[:class_method]
    class_name.meta_eval do
      eval body
    end
  else
    class_name.send(:class_eval, body)
  end
end