| [jakarta.ee-spec] @JsonbRequired for JSONB and JSON Schema |
Hi all,
I’d like to follow up on some discussions around the @JsonbRequired introduced.
https://github.com/eclipse-ee4j/jsonb-api/pull/285
On the feature itself, I clearly see some benefits to have validation happening before the bean is constructed and fields populated with the JSON payload. Good feature.
On the other hand, I don’t think @JsonbRequired is a good way to achieve it.
Basically I see 2 options for validation
payload validation
bean validation
@JsonbRequired in the bean to do payload validation does not seem accurate to me. It will set us for failure in the future.
If we want to address bean validation, we should consider having some integration of Bean Validation using Bean Validation annotations. Of course, this means validation will happen after the bean is constructed, but it also is way richer than “is the field required or not”. Users will be able to reuse constraints and implement business logic validation.
I agree that validating the payload before the object gets constructed is very interesting. But then, we should use JSON Schema for it. I am ok to create JSON Schema equivalent annotations, at least for the stable subset and the most interesting rules. From there, we can generate the JSON Schema, and feed the JSON Parser with it so the parser can effectively validate the payload before with a valid JSON Schema (same way an XML parser would get the XSD to validate the payload in JAXB).
Having @JsonbRequired seems to be in the middle and a hack for a very simple use case. I would not introduce it now and give us more time to discuss and think about the payload validation a bit more.
The hack has been introduced to solve an issue with the design of @JsonbCreator. See https://github.com/eclipse-ee4j/jsonb-api/issues/121
Again the design for @JsonbCreator and the need for the feature is awesome for immutable objects. The way to solve it with @JsonbRequired is messy.
Moreover, if we look at MicroProfile and OpenAPI, we are also half way because OpenAPI has @Schema, for instance
@Schema(type = SchemaType.OBJECT, implementation = InventoryList.class)
or
@Schema(required = true)
private final String hostname;
>From there, we generate an openapi document with all constraints (not a JSON Schema but pretty close).
Let’s say we need business validation or cross fields validations, we’ll use Bean Validation.
Let’s say we want OpenAPI documentation, we’ll use OpenAPI @Schema
And now let’s say we want JSON Payload validations, we’ll use @JsonbRequired?
Can we maybe consider the schema validation as a whole?
We could use the same set of annotations to generate the OpenAPI documentation and to generate the JSON Schema for the JSON Parser.
Thoughts?
I am happy to create an issue to revert @JsonbRequired if there is a consensus to wait.