Altwins are a last resort mechanism. When the parameterization of the model and the extension points for manual code are not able to get some functionality to work then altwins allow those kind of changes.

An altwin replaces a bit of code with another bit of code. It searches all the code files through the wildcard you provide and makes the code replacement anywhere it finds it during generation. This allows to intervene in framework base classes and override generated code in certain places.

But this comes with a high price:

• Generated code can change from version to version. One character out of position is enough for the altwin to fail the replacement

• You can easily cause unintended mass replacements if your search string is too generic

• Replaced code cannot be easily identified and contained by the generator

• A bug was found and you want to patch it on your current version and plan you version migration

• You are developing new patterns and need to test framework change sets to make it work