names.rb

class Task
  attr_accessor :name
  attr_accessor :assigned_to_user_id
  attr_accessor :due_on

  def save
    Storer.store(self)
  end
end

class EmailInfo

  def initialize(obj)
    @obj = obj
    @type = obj.class
  end

  def user_id
    @obj.send(id_fields[@type])
  end

  def title
    mapped_data[@type][:title]
  end

  def body
    mapped_data[@type][:body]
  end

  def id_fields
    {
      Task => :assigned_to_user_id,
      SomeThingElseMaybeUser => :id,
      MaybeEvent => :user_id
    }
  end

  def email_data
    {
      Task => { :title => "New Task", :body => "You have been assigned a new task" },
      SomeThingElseMaybeUser => { :title => "Thanks for registering", :body => "Have fun" },
      MaybeEvent => { :title => "New Event", :body => "Enjoy!" }
    }
  end

end

class Storer

  def self.store(obj)
    obj.save!
    email_info = TaskEmailInfo.new(obj)
    email.send(email_info.user_id, email_info.title, email_info.body)
  end
end

Suppose you wanted to save a task, but didn't want it to send an email? How would you suppress the email?