The Generation Gap Pattern (see also John Vlissides) is widely used to separate generated code from modifdied/extended code.

But the Generation Gap Pattern isn't always aplicable - from my experiences it fails if you generate code into areas with partly complex inheritance hierarchies like Persistence Layer with Entity, Embeddable, EJB3 etc.

Using a modern Generation Framework as oAW (openArchitectureWare) from Eclipse Modeling Tools Project you can implement a Veto Strategy in your workflow components to optimize file handling using Generation Gap Pattern.

In this presentation I introduce a VetoRedirectStrategy to find ways without applying the Generation Gap Pattern.

I tried to make a presentation partly in ZEN style and with easy-to-understand slides - so have fun.

references:

(c) 1996 John Vlissides "Generation Gap Pattern"

http://www.research.ibm.com/designpatterns/pubs/gg.html

Article Heike Behrens "Generation Gap Pattern"

http://www.1160pm.net/2009/04/23/generation-gap-pattern/

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