class SafeGetter
  attr_accessor :receiver
 
  def self.safe_nil
    @safe_nil ||= SafeGetter.new(nil)  
  end
 
  def initialize(r)
    @receiver = r
  end
 
  def to_s
    @receiver.to_s
  end
 
  def method_missing(methodname, *args)
    (@receiver.respond_to? methodname) ? SafeGetter.new(@receiver.send(methodname)) : SafeGetter.safe_nil
  end
end
 
# SafeGetter.new(@user).course.book.title.name.to_s => ''