Ruby使用设计模式中的代理模式与装饰模式的代码实例

代理模式

需求：

小明让小李替他追小丽（送洋娃娃，送花，送巧克力）

没有代理的代码：

# -*- encoding: utf-8 -*-

#追求者类
class Pursuit
 attr_accessor :mm

 def initialize(mm)
  @mm = mm
 end

 def give_dolls
  puts "#{mm.name} 送你洋娃娃"
 end

 def give_flowers
  puts "#{mm.name} 送你鲜花"
 end

 def give_chocolate
  puts "#{mm.name} 送你巧克力"
 end

end

#被追求者类
class Girl
 attr_accessor :name

 def initialize(name)
  @name = name
 end
end

xiao_hong = Girl.new('小红')

xiao_ming = Pursuit.new(xiao_hong)
xiao_ming.give_dolls
xiao_ming.give_flowers
xiao_ming.give_chocolate

只有代理的代码：

# -*- encoding: utf-8 -*-

#代理类
class Proxy
 attr_accessor :mm

 def initialize(mm)
  @mm = mm
 end

 def give_dolls
  puts "#{mm.name} 送你洋娃娃"
 end

 def give_flowers
  puts "#{mm.name} 送你鲜花"
 end

 def give_chocolate
  puts "#{mm.name} 送你巧克力"
 end

end

#被追求者类
class Girl
 attr_accessor :name

 def initialize(name)
  @name = name
 end
end

xiao_hong = Girl.new('小红')

xiao_ming = Proxy.new(xiao_hong)
xiao_ming.give_dolls
xiao_ming.give_flowers
xiao_ming.give_chocolate

只是把追求者类换成了代理类。

实际的代理模式代码：

# -*- encoding: utf-8 -*-

#公共接口module
module GiveGift
 def give_dolls
 end

 def give_flowers
 end

 def give_chocolate
 end
end

#追求者类
class Pursuit
 include GiveGift
 attr_accessor :mm, :name

 def initialize(mm)
  @mm = mm
 end

 def give_dolls
  puts "#{mm.name} 替#{name}送你洋娃娃"
 end

 def give_flowers
  puts "#{mm.name} 替#{name}送你鲜花"
 end

 def give_chocolate
  puts "#{mm.name} 替#{name}送你巧克力"
 end

end

#代理类
class Proxy
 include GiveGift
 attr_accessor :gg

 def initialize(mm)
  @gg = Pursuit.new(mm)
 end

 def give_dolls
  gg.give_dolls
 end

 def give_flowers
  gg.give_flowers
 end

 def give_chocolate
  gg.give_chocolate
 end

end

#被追求者类
class Girl
 attr_accessor :name

 def initialize(name)
  @name = name
 end
end

xiao_hong = Girl.new('小红')

xiao_ming = Proxy.new(xiao_hong)
xiao_ming.gg.name = '小明'
xiao_ming.give_dolls
xiao_ming.give_flowers
xiao_ming.give_chocolate

装饰模式
 
需求：

给人搭配不同的服饰

代码版本一

# -*- encoding: utf-8 -*-

class Person
 attr_accessor :name

 def initialize(name)
  @name = name
 end

 def wear_t_shirts
  puts '大T恤'
 end

 def wear_big_trouser
  puts '垮裤'
 end

 def wear_sneakers
  puts '破球鞋'
 end

 def wear_suit
  puts '西装'
 end

 def wear_tie
  puts '领带'
 end

 def wear_leather_shoes
  puts '皮鞋'
 end

 def show
  puts "*****装扮的#{name}\n\n"
 end

end

xc=Person.new('小菜')
puts "******第一种装扮"
xc.wear_t_shirts
xc.wear_big_trouser
xc.wear_sneakers
xc.show

puts "******第二种装扮"
xc.wear_suit
xc.wear_tie
xc.wear_leather_shoes
xc.show

这样写的话，功能是实现了，问题是如果增加“超人”的装扮，就要修改Person类，违反了开放-封闭原则。

代码版本二

# -*- encoding: utf-8 -*-

class Person
 attr_accessor :name

 def initialize(name)
  @name = name
 enddef show
  puts "*****装扮的#{name}\n\n"
 end

end

class Finery
 def show
 end
end

class TShirts < Finery
 def show
  puts '大T恤'
 end
end

class BigTrouser < Finery
 def show
  puts '垮裤'
 end
end

class Sneakers < Finery
 def show
  puts '破球鞋'
 end
end

class Suit < Finery
 def show
  puts '西装'
 end
end

class Tie < Finery
 def show
  puts '领带'
 end
end

class LeatherShoes < Finery
 def show
  puts '皮鞋'
 end
end

xc=Person.new('小菜')
ts = TShirts.new
bt = BigTrouser.new
sk = Sneakers.new
puts "******第一种装扮"
ts.show
bt.show
sk.show
xc.show

suit = Suit.new
tie = Tie.new
ls = LeatherShoes.new
puts "******第二种装扮"
suit.show
tie.show
ls.show
xc.show

这样改了之后，如果增加超人装扮，确实不需要去修改Person类。存在的问题是，各种衣服是独立的，并且暴露在外边的，就是一件一件穿的，没有顺序，没有控制。

代码版本三

# -*- encoding: utf-8 -*-

class Person
 attr_accessor :name

 def initialize(name=nil)
  @name = name
 end

 def show
  puts "*****装扮的#{name}\n\n"
 end

end

class Finery < Person
 attr_accessor :componet

 def decorate(componet)
  @componet = componet
 end

 def show
  componet.show if componet
 end
end

class TShirts < Finery
 def show
  super
  puts '大T恤'
 end
end

class BigTrouser < Finery
 def show
  super
  puts '垮裤'
 end
end

class Sneakers < Finery
 def show
  super
  puts '破球鞋'
 end
end

class Suit < Finery
 def show
  super
  puts '西装'
 end
end

class Tie < Finery
 def show
  super
  puts '领带'
 end
end

class LeatherShoes < Finery
 def show
  super
  puts '皮鞋'
 end
end

xc=Person.new('小菜')
ts = TShirts.new
bt = BigTrouser.new
sk = Sneakers.new
puts "******第一种装扮"
ts.decorate xc
bt.decorate ts
sk.decorate bt
sk.show

suit = Suit.new
tie = Tie.new
ls = LeatherShoes.new
puts "******第二种装扮"
suit.decorate xc
tie.decorate suit
ls.decorate bt
ls.show