Question

我在下面实现了这个例子，以便在Ruby上使用Observer Pattern。我尝试了this，但没有效果。

require "observer"

class AAnyClass
  extend Observable
  changed
  notify_observers self
end

module AnObserver

  extend self

  def update constant
    p "Constant #{constant} has been called."
  end

  def observe constant
    constant.add_observer(self)
  end

end

AnObserver.observe AAnyClass
# must return "Constant AAnyClass has been called."
AAnyClass
# must return "Constant AAnyClass has been called."
AAnyClass

更新

我将模块AnObserver转换为类，如下所示：

class AnObserver

  def update constant
    $stdout.puts "Constant #{constant} has been called."
  end

end

更改类AAnyClass，将Observable方法添加到构造函数中，并将AnObserver实例作为参数传递给方法add_observer，如下所示：

class AAnyClass
  include Observable

  def initialize
    add_observer AnObserver.new
    changed
    notify_observers AAnyClass
  end

end

最后，我添加了一些代码，使用eigenclass构造函数的相同代码修改了AAnyClass AAnyClass’s。

class << AAnyClass
  extend Observable

  add_observer AnObserver.new
  changed
  notify_observers AAnyClass
end
AAnyClass

AAnyClass.new
AAnyClass.new

就是这样。

Answer 1

我认为你正在使用模块和＃34;扩展＆＃34;你应该在哪里使用课程＆＃34;包括＆＃34;。这样的事情可能是你正在寻找的东西：

require "observer"

class AAnyClass
  include Observable

  def run
    changed
    notify_observers(self)
  end
end

class AnObserver

  def initialize(ob)
    ob.add_observer(self)
  end

  def update constant
    p "Constant #{constant} has been called."
  end

  def observe constant
    constant.add_observer(constant)
  end

end

ob = AAnyClass.new
AnObserver.new ob
ob.run

观察者模式不适用于Ruby

1 个答案: