意味のない継承を構造体に置き換える

修正前

クラス構成

module MailSendLog class Base class << self def post(param) data = default_data.merge( param: param ) @logger.post(@tag, data) end def default_data { tag: tag, specific_item: specific_item, } end def tag raise NotImplementedError, "must implement #{self.class}##{__method__}" end def specific_item raise NotImplementedError, "must implement #{self.class}##{__method__}" end end end end module MailSendLog class Recommend1 < MailSendLog::Base class << self protected def tag :recommend1 end def specific_item '固有の値1' end end end end module MailSendLog class Recommend2 < MailSendLog::Base class << self protected def tag :recommend2 end def specific_item '固有の値2' end end end end

使用時

MailSendLog::Recommend1.post('paramter') MailSendLog::Recommend2.post('paramter')

修正後

class MailSendLog MailType = Struct.new(:tag, :specific_item) Recommend1 = MailType.new(:recommend1, '固有の値1') Recommend2 = MailType.new(:recommend2, '固有の値2') def initialize(mail_type) @tag = mail_type.tag @max_item_count = mail_type.max_item_count @logger = Fluent::Logger::ConsoleLogger.open(STDOUT) end # continue methods... end

使用時

mail_send_log = MailSendLog.new(MailSendLog::Recommend1) mail_send_log.post('paramter') mail_send_log = MailSendLog.new(MailSendLog::Recommend2) mail_send_log.post('paramter')

利点

• 差分を埋める程度で大したことをしていない、無意味な継承をなくせる

class Struct (Ruby 2.6.0)