在类中的每个方法之前运行代码(Ruby)

Question

我想跟踪在我构建的类的实例上运行的所有方法.

目前我这样做:

class MyClass
    def initialize
        @completed = []
    end

    # Sends a welcome and information pack to the person who requested it
    def one_of_many_methods
    unless @completed.include? __method__
            # Do methody things
            @completed.push __method__
        end
    end
    alias :another_name :one_of_many_methods
    # Calling myClassInstance.another_name will insert
    # :one_of_many_methods into @completed.
    # Methody things should not now be done if .another_name
    # or .one_of_many_methods is called.
end

但是当我在班上有很多方法时,这会非常费力.我在重复自己!有没有办法跟踪被调用的方法,并且只允许它们被调用一次,就像我上面所做的那样,但是不必在每个方法中重复那个块？

谢谢!

(PS.我正在使用Ruby 1.9)

Answer 1

这听起来像是Proxy对象的完美用例.幸运的是,Ruby的动态性使得实现起来非常简单:

class ExecuteOnceProxy

  def initialize(obj)
    @obj = obj
    @completed = []
  end

  def method_missing(method, *args)
    unless @completed.include?(method)
      args.empty? ? @obj.send(method) : @obj.send(method, args)
      @completed << method
    end
  end
end

只需在构造函数中传递原始对象即可初始化代理:

proxy = ExecuteOnceProxy.new(my_obj)