Week 2, Day 3

Wednesday has started as usual - I got up around 6:45, had a shower and headed to MA, arriving at 8:10. I did some light reading about the Single Responsibility principle and headed down for our standup at 9:00. Our research project today is to research Inheritance vs Composition.

I have also received my feedback on the weekend challenge (building an Airport). I had two classes and 2 modules and my modules were doing the heavy lifting. Alas, looks like I overcomplicated everything rather than simplifying it. For example:

module AirController

  WEATHER = [:sunny, :stormy]

  def permission_to_land(*plane)
    fail "The Airport is full" if plane_hangar_full?
    fail "Bad weather conditions" if weather_stormy?
    plane_landed(*plane)
  end

  def permission_to_take_off(*plane)
    fail "No planes at the airport" if plane_hangar_empty?
    fail "Bad weather conditions" if weather_stormy?
    plane_took_off(*plane)
  end

  private

  def plane_landed(*plane)
    x = plane.each { |plane| plane.landing }
    planes << x.flatten
    planes.flatten!
  end

  def plane_took_off(*plane)
    plane.each { |plane| plane.take_off }
    planes.delete_if { |plane| plane.flying }
  end

  def weather_forecast
    WEATHER.sample
  end

  def weather_stormy?
    weather_forecast == :stormy
  end

end

As you can see my AirController module was looking after the planes states, creating an unwanted dependency.

My other module took over the Airport’s functions

module PlaneHangar

  attr_writer :capacity

  DEFAULT_CAPACITY = 6

  def planes
    @planes ||= []
  end

  def capacity
    @capacity ||= DEFAULT_CAPACITY
  end

  private

  def plane_hangar_full?
    planes.length >= capacity
  end

  def plane_hangar_empty?
    planes.empty?
  end

end

…making my Airport a dependant.

require_relative 'aircontroller'
require_relative 'planehangar'
require_relative 'plane'

class Airport
  include AirController
  include PlaneHangar

  def initialize(capacity = PlaneHangar::DEFAULT_CAPACITY)
    self.capacity = capacity
    self.planes
  end

end

Overall, I need to stop and think about the classes’ responsibilities (SRP - Single Responsibility Principle) and take it from there, making my code TRUE (Transparent, Resonable, Usable, Exemplary).

Good night.

Zhivko