Design Pattern: Abstract Factory Pattern - Ruby Solution

factory_pattern.rb

# class Duck

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

#   def eat
#     puts "Duck #{@name} eats"
#   end

#   def speak
#     puts "Duck #{@name} speaks Quack!"
#   end

#   def sleep
#     puts "Duck #{@name} sleep silently"
#   end
# end

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

  def eat
    puts "Frog #{@name} eats"
  end

  def speak
    puts "Frog #{@name} says Crooooooooaaakkk!"
  end

  def sleep
    puts "Frog #{@name} doesn't sleep; he croaks all night!"
  end
end

# class Pond

#   ## Deciding the responsible class at runtime while calling. Thats why its Factory Method Pattern
#   def initialize(number_animals)
#     @animals = []
#     number_animals.times { |i| @animals << new_animal("Animal#{i}") }
#   end

#   def simulate_one_day
#     @animals.each { |animal| animal.eat }
#     @animals.each { |animal| animal.speak }
#     @animals.each { |animal| animal.sleep }
#   end
# end

# class DuckPond < Pond

#   def new_animal(name)
#     Duck.new(name)
#   end
# end

# class FrogPond < Pond

#   def new_animal(name)
#     Frog.new(name)
#   end
# end

class Tree

  def initialize(name)
    @name = name
  end

  def grow
    puts "Tree #{@name} grows tall"
  end
end

class Tiger

  def initialize(name)
    @name = name
  end

  def eat
    puts "Tiger #{@name} eats anything it wants"
  end

  def speak
    puts "Tiger #{@name} Roars!"
  end

  def sleep
    puts "Tiger #{@name} sleeps anywhere it wants"
  end
end

class WaterLily

  def initialize(name)
    @name = name
  end

  def grow
    puts "The Water Lily #{@name} floats, soaks up the sun, and grows"
  end
end

class OrganismFactory

  def initialize(plant_class, animal_class)
    @plant_class = plant_class
    @animal_class = animal_class
  end

  def new_animal(name)
    @animal_class.new(name)
  end

  def new_plant(name)
    @plant_class.new(name)
  end
end

# class JungleOrganismFactory

#   def new_animal(name)
#     Tiger.new(name)
#   end

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

# class PondOrganismFactory

#   def new_animal(name)
#     Frog.new(name)
#   end

#   def new_plant(name)
#     WaterLily.new(name)
#   end
# end

class Habitat

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

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

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

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

# duckpond = DuckPond.new(3)
# duckpond.simulate_one_day
# frogpond = FrogPond.new(3)
# frogpond.simulate_one_day

# jungle = Habitat.new(1, 4, JungleOrganismFactory.new)
jungle_organism_factory = OrganismFactory.new(Tree, Tiger)
jungle = Habitat.new(1, 4, jungle_organism_factory)
jungle.simulate_one_day

# pond = Habitat.new(2, 4, PondOrganismFactory.new)
pond_organism_factory = OrganismFactory.new(WaterLily, Frog)
pond = Habitat.new(2, 4, pond_organism_factory)
pond.simulate_one_day