Custom annotation processing during Jakarta XML schemagen

Question

I want to generate an XSD schema for existing, jaxb annotated, DTO's. I can't easily change the DTO code or the serialization formats. I have two problems:

• The DTO's use custom validation annotations which I would like to translate into xsd restrictions
• The DTO's use XmlAdapters to flatten e.g. numbers and dates into various string formats. It is important to add information about which adapter is used to the xsd, e.g. floating points could be formatted into various formats with 2-4 significant digits without separator so the parsing side must know which format to expect. Ideally the fields would have annotations for the xml simpleTypes, but they don't

How do I generate the simpleType based on @JavaXmlTypeAdapter annotations? How do I inject validation constraints based on custom annotations?

I read the documentation for jaxb and various maven plugins but could not find a solution.

• Is there a builtin way to generate xsd types based on @XmlJavaTypeAdapter annotations?
• highsource/jaxb-tools does not seem to support schemagen at all
• mojohaus/jaxb2-maven-plugin can inject javadoc in a postprocessing step, but the machinery seems hardcoded for javadoc
• whummer/jaxb-facets can generate xsd constraints from annotations but seems affected by bitrot