Better optional properties with Jackson

[danielkaneider]

Hi,

I'm creating a follow-up of #250. The current possibilities still feel very limiting to me.

Current pain points

1. Currently a primitive property is not considered as non-optional when using useLibraryDefinition
2. It is not possible to use useLibraryDefinition and useSpecifiedAnnotations at the same time

How it should work

• primitives such as int getNumber() should not be optional
• all other objects eg String getText() should default to library
• annotations specified (NonNull/Nullable) could overrule this

Suggestions

1. Jackson2Parser line 229 should be rather !beanPropertyWriter.isRequired() && !beanPropertyWriter.getType().isPrimitive()
2. It would be nice if there is a OptionalProperties.useLibraryAndAnnotations

[vojtechhabarta]

Hi,

your proposal seems good. Problem is with primitive types because changing how they are handled would be breaking change.

I am thinking about adding requiredAnnotations parameter (see #443). Properties would be optional by default when using requiredAnnotations and required by default when using optionalAnnotations (as it is now). Only one of optionalAnnotations and requiredAnnotations could be used. Would that help you somehow or would it change your proposal?

[danielkaneider]

Yes, #443 sounds exactly like our use-case. I'd suggest to name it nonNullAnnotations (rather than requiredAnnotations) as there is a javax.annotation.NonNull and a org.checkerframework.checker.nullness.qual.NonNull already. Please also keep in mind that checking for (required|optional)Annotations.isEmpty() is not really straight-forward for the user. I'd bind it to an additional setting (eg. OptionalProperties).

Regarding primitives, I know about backwards-compatibility. Thats why I suggested OptionalProperties.useLibraryAndAnnotations which could introduce also the change with the primitives.

[vojtechhabarta]

Regarding configuration parameter naming: I think we are dealing with two things from TypeScript:

1. properties that can be optional or required (this is TypeScript terminology)
2. nullability of types (also TypeScript terminology)

For example lib.es5.d.ts TypeScript file contains types Required<T> and NonNullable<T>.

So for properties I would use optionalAnnotations and requiredAnnotations while for types I would use nullableAnnotations (and leave nonNullableAnnotations for non-nullable types should we need it in the future).

[vojtechhabarta]

Parameter requiredAnnotations is released in v2.21.588.