Holes in the specification of attribute converters

[gavinking]

AFAICT, nowhere does the spec say how to determine the target type of an AttributeConverter.

UPDATE: in fact, the spec as written is not even clear at all as to what is a legal "target" type, and what is a legal converted type.

[gavinking]

Something else I ran into: in the javadoc it's lightly-implied that @Convert with no converter and no disableConversion may be used to apply a non-auto-apply converter, which looks useful and totally makes sense.

But then this is contradicted (clarified?) in the spec which says that in fact the behavior in this case is undefined.

I would formalize what is implied by the Javadoc. Annotating a field @Convert should look for a suitable converter and apply it. There's no need to explicitly specify the converter class unless there is an ambiguity.

[gavinking]

I've found another hole here. The spec mentions three cases for use of @Convert:

1. "applied to a basic attribute or to an element collection of basic type"
2. "applied to an embedded attribute or to a map collection attribute whose key or value is of embeddable type"
3. " applied to an entity class that extends a mapped superclass"

and it says:

• "When .. applied to a map containing instances of embeddable classes, the attributeName element must be specified, and "key." or "value." must be used"
• "When .. applied to a map to specify conversion of a map key of basic type, "key" must be used"

What about:

1. Can @Convert be used with non-map collections of embeddables?
2. For a map value of basic type can/must "value" be used?