Option to exclude generating Java classes of imported types

[mjunsilo]

We are importing DKPro types that have handcrafted Java implementations in the next release. Modules, that rely on those handcrafted method implementations not available in a code generated class, will fail if the handcrafted type is not found first in the classpath.

It would be easier to manage if we could just disable generating Java classes of imported types, preferably if they could be excluded/included based on regex patterns. However, a simple on/off switch for generating imported types would be a good start.

The JCasGen Maven plugin seems to have such an option already:

https://issues.apache.org/jira/browse/UIMA-2958