;; connection pool
(defvar *connection-pool* nil)

;; アプリケーションサーバが立ち上がるときに実行
(defun init-database (driver-name &rest params &key database-name &allow-other-keys)
  "initialize database"
  (setf *connection-pool* (apply #'dbi-cp:make-dbi-connection-pool driver-name params)))

;; アプリケーションサーバ終了時に実行
(defun shutdown-database ()
  (dbi-cp:shutdown *connection-pool*))

;; こんな感じのマクロを定義
(defmacro transactional ((db) &body body)
  "transactional macro like SpringFramework"
  `(let ((,db (batis:create-sql-session *connection-pool*)))
     (handler-case
         (progn
           ,@body)
       (error (e)
         (progn
           (batis:rollback ,db)
           e))
       (:no-error (c)
         (batis:commit ,db)
         c))))


;; サービス層でこんな感じで使いたい
(defun foo-service (&rest params)
  "this is service"
  (transactional (db)
    (check-parameters params)
    (register-user db params)
    (fetch-user db params)))


;; こんな感じでやりたいけど db っていうパラメータが見えなくなるのでちょっと嫌な感じ
@Transactional
(defun foo-service (&rest params)
  "this is service"
  (check-parameters params)
  (register-user db params)
  (fetch-usre db params))