# Subject
class Graphic
    def initialize(file_name)
        @file_name = file_name
    end

    def get_file_name()
        return @file_name
    end
end

# RealSubject
class Image < Graphic
    def initialize(file_name)
        super(file_name)
    end

    # Request()
    def draw()
        puts "draw " + @file_name
    end
end

# Proxy
class ImageProxy < Graphic
    def initialize(file_name)
        super(file_name)
        @image = nil
    end

    def draw()
        get_image().draw()
    end

    def get_image()
        if @image == nil
            @image = Image.new(@file_name)
        end
        return @image
    end
end

# Client
proxy = ImageProxy.new("1.png")
# operation without creating a RealSubject
fileName = proxy.get_file_name()
# forwarded to the RealSubject
proxy.draw()

puts "fileName is #{fileName}"