to_update = self.all(
      :conditions => [
        'status = ? AND handler IS NULL AND (dont_send_after IS NULL OR dont_send_after > ?) '+ \
        'AND (dont_send_before IS NULL OR dont_send_before <= ?)',
        STATUS[:unsent], time_now, time_now
      ],
      :order => [:id], :limit => number
    )

    to_update.size

    to_update.update!(
        :status => STATUS[:locked_to_send],
        :handler => handler
    )