require 'logger'
$log = Logger.new(STDOUT)
$log.level = Logger::INFO
$log.progname = "LifecycleDemo"
$log.formatter = proc { |severity, datetime, progname, msg|
    #"#{datetime.strftime("%Y-%b-%d %a %H:%M")} #{severity} #{progname} {#{msg}}\n"
    "#{msg}\n"
  }
#$log.datetime_format = "%a %Y-%m-%d %H:%M"


class FirstClass
  @@grandClass = "FirstClassVar" # class level variable to track
  def initialize
    @grandVar = "FirstInstanceVar" # instance variable to track
    $log.info("! FirstClass init, #{ids}")
  end
  def grand
    $log.info("> FirstClass grand, #{ids}")
  end

  def ids
      "#{self.class.name}:: #{@@grandClass}:#{@@grandClass.object_id}, #{@grandVar}:#{@grandVar.object_id}"
  end
end

class SecondClass < FirstClass
  def initialize
    @ego_hilite = "-" * 15
    super
    $log.info("! Second class init, #{ids}")
  end
  def spill_it
    $log.info("> Spill It call, #{ids}")
  end
  def alter_ego
      @grandVar = "SecondInstanceVar"
      @@grandClass = "SecondClassVar"
      $log.info("\n#{@ego_hilite} Ego altered by the #{self.class.name} #{@ego_hilite}\n\n")
  end
end

class ThirdClass < SecondClass
  @@grandClass = "ThirdClassStatic"
  def initialize
    super
    $log.info("! 3rd class init, #{ids}")
  end
  def alter_ego
      @grandVar = "ThirdInstanceVar"
      @@grandClass = "ThirdClassVar"
      $log.info("\n#{@ego_hilite} Ego altered by the Third Class #{@ego_hilite}\n")
  end
end

def test(instance)
    hilite = "*" * 20
    $log.info("\n\n#{hilite} Testing instance of #{instance.class.name} BEGIN #{hilite}")
    instance.grand
    instance.spill_it

    # see what gets changed if anything:
    instance.alter_ego

    instance.grand
    instance.spill_it
    $log.info("\n#{hilite} Testing instance of #{instance.class.name} END #{hilite}")
end

test(SecondClass.new)
test(ThirdClass.new)

class FirstClass
  @@grandClass = "FirstClassVar" # class level variable to track
  def initialize  
    @grandVar = "FirstInstanceVar" # instance variable to track
    puts "! FirstClass init, #{ids}"  
  end  
  def grand
    puts "> FirstClass grand, #{ids}"  
  end  

  def ids
      "#{self.class.name}:: #{@@grandClass}:#{@@grandClass.object_id}, #{@grandVar}:#{@grandVar.object_id}"
  end
end  
  
class SecondClass < FirstClass
  def initialize  
    @ego_hilite = "-" * 15
    super  
    puts "! Second class init, #{ids}"  
  end  
  def spill_it
    puts "> Spill It call, #{ids}"  
  end
  def alter_ego
      @grandVar = "SecondInstanceVar"
      @@grandClass = "SecondClassVar"
      puts "\n#{@ego_hilite} Ego altered by the #{self.class.name} #{@ego_hilite}\n\n"
  end
end  
  
class ThirdClass < SecondClass
  @@grandClass = "ThirdClassStatic"
  def initialize  
    super  
    puts "! 3rd class init, #{ids}"  
  end  
  def alter_ego
      @grandVar = "ThirdInstanceVar"
      @@grandClass = "ThirdClassVar"
      puts "\n#{@ego_hilite} Ego altered by the Third Class #{@ego_hilite}\n"
  end
end  

def test(instance)
    hilite = "*" * 20
    puts "\n\n#{hilite} Testing instance of #{instance.class.name} BEGIN #{hilite}"
    instance.grand
    instance.spill_it

    # see what gets changed if anything:
    instance.alter_ego

    instance.grand
    instance.spill_it
    puts "\n#{hilite} Testing instance of #{instance.class.name} END #{hilite}"
end

test(SecondClass.new)
test(ThirdClass.new)

class FirstClass
  @@grandClass = "FirstClassVar" # class level variable to track
  def initialize  
    @grandVar = "FirstInstanceVar" # instance variable to track
    puts "! FirstClass init, #{ids}"  
  end  
  def grand
    puts "> FirstClass grand, #{ids}"  
  end  

  def ids
      "#{@@grandClass}:#{@@grandClass.object_id}, #{@grandVar}:#{@grandVar.object_id}"
  end
end  
  
class SecondClass < FirstClass
  def initialize  
    super  
    puts "! Second class init, #{ids}"  
  end  
end  
  
class ThirdClass < SecondClass
  def initialize  
    super  
    puts "! 3rd class init, #{ids}"  
  end  
  def spill_it
    puts "> Spill It method call from 3rd class, #{ids}"  
  end
  def alter_ego
      @grandVar = "ThirdInstanceVar"
      @@grandClass = "ThirdClassVar"
      puts "\n#{"*" * 15} Ego altered by the Third Class #{"*" * 15}\n\n"
  end
end  

third = ThirdClass.new  

third.grand
third.spill_it

# see what gets changed if anything:
third.alter_ego

third.grand
third.spill_it

Ruby class and instance variables lifecycle across inheritance demo

ruby

Ruby