[Springframework-developer] Example of declarative transactions with AOP

[Rod J. <rod...@in...>]

This is a rough example, not meant as a guide to good practice, but just my
play area... Hence the use of SQL queries for everything, rather than cached
data.

However, it does show declarative tx mgt via AOP, and the tx rollback works
nicely.

The AOP stuff is in the test-servlet.xml bean file. Note how the bank target
is an implementation of the bo.Bank interface, while the publicly exposed
bank object is an AOP proxy. The declarative tx behaviour is specified by
the transactionAttributeSource property of the transaction interceptor. Of
course the tx interceptor could be shared (like the datasource in Ken's
application) across all servlets by being specified in
applicationContext.xml.

Another interesting possibility is shown by making the createController
(which creates the tables) transactional via AOP. Of course you wouldn't
normally want to make a web controller transactional (preferring tx
delimitation in business objects) but it's transparent to the MVC
infrastructure, hence works nicely. Could be useful with legacy code.

The readonly interceptor to prevent a JSP from calling update methods is an
experiment with the idea of JSPs having limited access to domain objects,
without always needing a bean. Not sure about this. Of course it should
really be implemented via a ReadOnly metadata attribute rather than the
hardcoded interceptor as in the example.

The example works with the default HSQL db shipped with Orion 2.01.

Regards,
Rod