QueryBuilder can take abstract class

[igler]

Currently only non-abstract classes work for the following resolution of changes:

javers.findChanges(QueryBuilder.byClass(NotAnAbstractEntity.class).build());

If I try byClass with an abstract class nothing is returned. It would be nice if all subclasses are queried and changes on all of them are returned.

[bartoszwalacik]

Agreed that it would be nice, but I cant see obvious way of effective implementation of this query (without running table full scans)...

[bartoszwalacik]

In Java , there is no easy way to find all subclasses af a given class using Reflection API

[igler]

Maybe helpful: https://github.com/ronmamo/reflections

[bartoszwalacik]

Yeah , there are some libs for that but I really want to keep JaVers lightweight.

[igler]

BTW, how can I get all changes of all entities, ideally with Paging support?

[bartoszwalacik]

for now you cant, but it can be easily implemented, also we have a task about paging #179, ideal for contribution

[bartoszwalacik]

let me know if you would like to contribute these two things

[igler]

I think extending

public static QueryBuilder byClass(Class requiredClass)

to

public static QueryBuilder byClass(Class... requiredClasses)

could help so I can submit a list of classes and do reflections on my side?

[bartoszwalacik]

looks like a good idea

[igler]

See #246

[bartoszwalacik]

ok, but there is no implementation and no tests in this PR ...

[igler]

Method in line 38 of https://github.com/igler/javers/blob/b66bae9c7bd4add9269f023ba403ed25326398d6/javers-core/src/main/java/org/javers/repository/jql/QueryBuilder.java is additional.

[bartoszwalacik]

I've seen this method, but this is only a query.
you should write a test for this feature (in JaversRepositoryE2ETest),
second thing, looks like implementation for this Query in QueryRunner is missing