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stephenaument/create_ducks_migration1.rb

Created March 8, 2014 07:22
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The Null Object Pattern
Raw
create_ducks_migration1.rb
class CreateDucks < ActiveRecord::Migration
def change
t.string name
t.string status
t.integer hunger
t.string quack_style
t.string color
t.migratory boolean
end
end
Raw
create_ducks_migration2.rb
class CreateDucks < ActiveRecord::Migration
def change
t.string name
t.string status
t.integer hunger
t.string quack_style
t.string color
t.string secondary_color
t.migratory boolean
end
end
Raw
duck1.rb
class Duck < ActiveRecord::Base
def awake?
status == 'awake'
end
def quack
puts quack_style
end
end
Raw
duck2.rb
class Duck < ActiveRecord::Base
def awake?
status == 'awake'
end
def quack
puts quack_style
end
def multi_colored?
!secondary_color.nil?
end
end
Raw
javascript.js.haml
//javascript
{ multiColored: #{duck.multi_colored?} }
Raw
javascript1.js
// javascript
{ multiColored: } // !!! Not a valid JSON object, buddy!
Raw
javascript2.js
// javascript
{ multiColored: false }
Raw
nil_duck1.rb
class NilDuck
attr_writer :name, :status, :hunger, :quack_style, :color, :migratory
def name
'Demo Duck'
end
def status
'sleeping'
end
def hunger
nil
end
def quack
end
def quack_style
nil
end
def color
'gray'
end
def awake?
false
end
def migratory
nil
end
def migratory?
true
end
end
Raw
nil_duck2.rb
class NilDuck
def name
'Demo Duck'
end
def status
'sleeping'
end
def color
'gray'
end
def migratory?
true
end
def method_missing(name, *args)
Duck.new.respond_to?(name) ? nil : super
end
end
Raw
nil_duck3.rb
class NilDuck
def name
'Demo Duck'
end
def status
'sleeping'
end
def color
'gray'
end
def migratory?
true
end
def method_missing(name, *args)
super unless Duck.new.respond_to?(name)
name.ends_with?('?') ? false : nil
end
end
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