Product Description
This "how to" book shows how to improve the design of large information systems by designing for software reuse, incorporating object-orientated ideas, and adding a graphical user interface.
From the Author
Our book is a very good exploration of the perspective it
starts from - which is basically that objects are state machines (known as
entity life histories in SSADM).
It shows how a reusable method (or operation) is found where two or more
events (or business services) have the same effect, at the same state, in
the state machine of a persistent entity.
The most remarkable innovation is Keith Robinson's (partly automated)
derivation of event-oriented procedures from object-oriented state
machines. The assumption is that business services will be coded using the
pattern Martin Fowler now calls "transaction scripts".
The discussion is about method bodies. We considered and rejected dwelling
on interfaces. If we had done so, then we could have stolen a march on
SOA!
We were not enthusiastic about inheritance or polymorphism. I still believe
they are rarely useful in models of persistent business entities (despite
Martin Fowlers attempts to show otherwise in his examples of "domain model"
pattern).