Consider adding an isValid method

[RicoYao]

It would be nice if there was a method had to check if the model is "valid" in the sense that it contains the non-optional set of fields as defined by the schema. This method would allow for defense against invalid-json or mis-use of builders.

[rahul-malik]

Yeah a validation method would be nice and there are things beyond nullability that we might need to check.

A few ideas:

For invalid JSON:
The initializer that takes a json object should either throw an exception or fail to initialize a model (return null) in the case of an invalid input

Builders:
The generated setters for the builders should check for null in non null properties and fail accordingly (assert, throws, etc)

Thoughts?

[RicoYao]

For invalid JSON:
The initializer that takes a json object should either throw an exception or fail to initialize a model (return null) in the case of an invalid input

I like the idea, but it might be a bit too severe to throw out the entire model if, for example, a non-optional field is missing, but the rest of the model may still be of value. A minor back-end bug could lead to a more severe failure than is necessary. Of course that cuts both ways, because failing out early could also save us from severe bugs. I figured that having a model.isValid() method would let the implementer decide on that tradeoff.

Builders:
The generated setters for the builders should check for null in non null properties and fail accordingly (assert, throws, etc)

Makes sense. In addition to validation in the setters, I think we'd also want to validate during the build() phase. That way we also catch the condition where you failed to call the setter at all.

[RicoYao]

Just in case it wasn't clear, by "non-optional" field, I'm referring to the fields in the "required": [] block of the json schema.

[shashachu]

Having a Builder.build() method that can fail would require a bit more thought, i.e. it'd have to have a throws signature or be marked nullable. Both things could make the calling code a bit annoying.