Feature request: custom PersistentPropertyType with converter

[kktuax]

It would be great to support custom domain model types. Now with JPA you can define custom model property types, and a javax.persistence.Converter, for example for storing a joda-time Duration as a Long value:

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

import org.joda.time.Duration;

@Converter(autoApply = true)
public class DurationConverter implements AttributeConverter<Duration, Long>{

    @Override
    public Long convertToDatabaseColumn(Duration value) {
        if(value!=null){
            return value.getMillis();
        }
        return null;
    }

    @Override
    public Duration convertToEntityAttribute(Long value) {
        if(value!=null){
            return Duration.millis(value);
        }
        return null;
    }

}

It would be great to have some way of editing this type of fields. Detecting automatically JPA's converters I imagine it could be challenging, but maybe it could be achieved with something similar to FieldValueRenderer in formView.