Reusability of Code

I have given up trying to get the TPCC schema work as defined, i.e., using composite keys. Glassfish at present does not support Id Generators with composite keys, which poses a problem, as it means writing extra code for generating keys. As a workaround to this issue, I have modified the schema to use surrogate primary keys.

EJB persistence design favours Entity Relationships based upon surrogate primary keys.

One of the great benefits of EJB 3.0 is that it gets rid of all the boiler plate EJB code, allowing you to code Entity and Session beans as if they were POJOs. This raises the expectation that in this new world, it should be possible to write reusable code that is environment agnostic. By this I mean that I should be able to reuse my J2EE Business Logic classes and the Persistent classes in a J2SE or Servlet Container (Tomcat) environment without having to change any code.

There is an immediate stumbling block to achieving this, however. The unfortunate decision to introduce a new abstraction for Transaction Management for J2SE environment means that tranaction management code is not portable. The first rule for writing reusable code therefore is to avoid transaction management code in your classes. I will report on other pitfalls as I progress with my attempts to create reusable code.