Using the Transaction Script pattern - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 338

Transaction Script pattern, there are only three layers: the transaction scripts, the
DAO s, and the Spring/i BATIS class.
So far, we have implemented the transaction scripts and tested them using
mock DAO s. The next step in the process of implementing the transaction script-
based business logic is to implement those DAO s, which include PendingOrderDAO
and RestaurantDAO . As figure 9.6 shows, each DAO consists of an interface and an
implementation class. The interface makes it easy to swap implementations. It

<<interface>>
RestaurantDAO

<<interface>>
PendingOrderDAO

findAvailableRestaurants()
findRestaurant()

findOrCreatePendingOrder()
savePendingOrder()

RestaurantDAOImpl

PendingOrderDAOImpl

findAvailableRestaurants()
findRestaurant()

findOrCreatePendingOrder()
savePendingOrder()

PendingOrder.xml

<sqlmap>

<select ..>
SELECT *
FROM PENDING_ORDER
WHERE
</select>

org.
springframework.orm.iBatis

SqlMapClient
Template

SqlMapClient
DaoSupport

<insert... >
INSERT INTO PENDING _ORDER
...
</insert>

queryForList()
update()
delete()
...

getSqlMapClientTemplate()

<resultMap
class="PendingOrderDTO" ...>
...
</resultMap>

</sqlmap>

iBATIS

SqlMapClient

sqlMap-config.xml

queryForList()
update()
delete()
...

<sqlMapConfig>
<sqlMap resource="PendingOrder .xml" />
</sqlMapConfig>

Figure 9.6 iBATIS DAO classes and configuration files