Null Object Pattern example, extract from "Ben Orenstein - Refactoring from Good to Great, Boston Ruby August 2012" presentation. http://bostonrb.org/presentations/refactoring-a-live-coding-odyssey

1_before.rb

require "ostruct"

class JobSite
  attr_reader :contact

  def initialize(location, contact)
    @location = location
    @contact = contact
  end

  def contact_name
    if contact
      contact.name
    else
      'no name'
    end
  end

  def contact_phone
    if contact
      contact.phone
    else
      'no phone'
    end
  end

  def email_contact(email)
    if contact
      contact.deliver_email(email)
    end
  end
end

class Contact < OpenStruct
  def deliver_email(email)
    # ...
  end
end

2_after.rb

require "ostruct"

class JobSite
  attr_reader :contact

  def initialize(location, contact)
    @location = location
    @contact = contact || NullContact.new
  end

  def contact_name
    contact.name
  end

  def contact_phone
    contact.phone
  end

  def email_contact(email)
    contact.deliver_email(email)
  end
end

# Null Object Pattern
class NullContact
  def name
    'no name'
  end

  def phone
    'no phone'
  end

  def deliver_email
  end
end

class Contact < OpenStruct
  def deliver_email(email)
    # ...
  end
end

3_diff.diff

   def initialize(location, contact)
     @location = location
-    @contact = contact
+    @contact = contact || NullContact.new
   end
 
   def contact_name
-    if contact
-      contact.name
-    else
-      'no name'
-    end
+    contact.name
   end
 
   def contact_phone
-    if contact
-      contact.phone
-    else
-      'no phone'
-    end
+    contact.phone
   end
 
   def email_contact(email)
-    if contact
-      contact.deliver_email(email)
-    end
+    contact.deliver_email(email)
+  end
+end
+
+# Null Object Pattern
+class NullContact
+  def name
+    'no name'
+  end
+
+  def phone
+    'no phone'
+  end
+
+  def deliver_email
   end
 end

what happens when your object has 100 methods? copy 100 times the definition? and what about maintenance (if a method signature changes you need to update both files) ? sure metaprogramming might help but I don't see the real value here...

contact ? contact.name : 'no name'

is short and simple enough to me.
Moreover, using rails it can become

contact.try(:name)

just my 2 cents.

yeah I agree with you, personally I don't see a time when I'll use it in real life, especially in Rails.

I pasted these because this approach, or so called Null Object Pattern is new to me. Kind of inspring despite how we're gonna use it :)