factory_method.rb

# coding: utf-8

class Algae
  def initialize(name)
    @name = name
  end

  def grow
    puts "藻 #{@name} は日光浴を浴びて育っています"
  end
end

class Frog
  def initialize(name)
    @name = name
  end

  def eat
    puts "カエル #{@name} は食事中です."
  end

  def speak
    puts "カエル #{@name} はゲロッゲロッと泣きます."
  end

  def sleep
    puts "カエル #{@name} は眠りません."
  end
end

class Tree
  def initialize(name)
    @name = name
  end

  def grow
    puts "樹木 #{@name} が高く育っています"
  end
end

class Tiger
  def initialize(name)
    @name = name
  end

  def eat
    puts "トラ #{@name} は食べたいものを何でも食べます."
  end

  def speak
    puts "トラ #{@name} はガオーとほえています."
  end

  def sleep
    puts "トラ #{@name} は眠たくなったら眠ります."
  end
end

class PondOrganismFactory
  def new_animal(name)
    Frog.new(name)
  end

  def new_plant(name)
    Algae.new(name)
  end
end

class JungleOrganismFactory
  def new_animal(name)
    Tiger.new(name)
  end

  def new_plant(name)
    Tree.new(name)
  end
end

class Habiat
  def initialize(number_animals, number_plants, organism_factory)
    @organism_factory = organism_factory

    @animals = []
    number_animals.times do |i|
      animal = @organism_factory.new_animal("動物#{i}")
      @animals << animal
    end

    @plants = []
    number_plants.times do |i|
      plant = @organism_factory.new_plant("植物#{i}")
      @plants << plant
    end
  end

  def simulate_one_day
    @plants.each {|plant| plant.grow}
    @animals.each {|animal| animal.speak}
    @animals.each {|animal| animal.eat}
    @animals.each {|animal| animal.sleep}
  end

end

jungle = Habiat.new(1, 4, JungleOrganismFactory.new)
jungle.simulate_one_day

pond = Habiat.new(2, 4, PondOrganismFactory.new)
pond.simulate_one_day