Satish’s Blog

I have a singleton method in one of my service calls which I wanted to have memoize functionality. While there are several ways to do, I wanted to have a simple elegant way to do it. I have seen an example from Dave Thomas for instance methods. This one is similar to one of his examples but works for singleton methods. Comments are welcome.

module CacheHelper
  def cache(name)
    eigen_class = class << self
      self
    end
    eigen_class.instance_eval do
      memory = {}
      original = "original#{name}"
      alias_method(original, name)
      define_method(name) do |*args|
        if memory.has_key?(args)
          memory[args]
        else
          memory[args] = send original, *args
        end
      end
    end
  end
end