We have a legacy database whereby integers are stored as varchar padded with zeros, i.e. the value 1 is stored as 001 depending on the column length defined in the schema. The idea is to have each of the entities represent such information with the type Integer. To achieve this one would normally extend AttributeConverter, however, this only provides that attribute value to be converted. How can one gain access to the @Column annotation to retrieve the value for the length?
You can’t. The AttributeConverter doesn’t know anything about the use-site. You could create a converter for each length though, or you go the more complicated route and implement a custom UserType and also extend the org.hibernate.usertype.DynamicParameterizedType interface.
I did try creating a custom UserType however the conversion is only applied when reading from or writing to the database. For my use case, I would like that this is also applied to the values when used for filtering via a CriteriaBuilder. I do not know if this is a bug or if the UserType is intended to work in such a way.
If you share an example of what you tried but doesn’t work then I can help you. UserType conversion is applied for parameters which are compared against fields of that type though.