mandatory parameters

[aowss]

Hi,

typically a builder's constructor ( or static factory ) takes all the required parameters.
When generating the builder via Includes, is there a way to specify the required parameters ?

Thanks

[Randgalt]

Do you mean RecordInterface.Include? Maybe you can give an example?

[Randgalt]

I see - this relates somewhat to the discussion here: #30 i.e. how should validation annotations be handled. I should see what the Immutables library does with this and maybe try to emulate it. However, I really want to keep this library simple too.

[aowss]

Thanks for your prompt response and for this library.

I tried to summarize the options in this doc.
What i like with this library is the ability to not annotate the model ( that is very important to me ) but having the mandatory parameters part of the generated builder constructor is also important.
I think it is not exactly the same as the discussion you reference since this is part and parcel of the builder pattern.

Let me know what you think. Whatever you decide to do, good work!

[Randgalt]

Great doc with very a thoughtful description of the issue. Bundling this with #30 we get...

1. Should RecordBuilder do anything in particular with validation annotations
2. Should RecordBuilder offer specialized constructors and/or helpers beyond what the language offers for records?

For 1, we could do:

• Nothing
• Copy any annotations without further processing
• Have RecordBuilder notice common annotations such as NotNull and do further processing such as what the Immutables library does
• Have RecordBuilder optionally pass built objects through a JSR-303 validator

For 2, we could

• Rely on the solution to 1 above - i.e. the validation annotations are sufficient
• Do nothing
• Create alternate ctors as described in @aowss's document

[Randgalt]

See proposal here: #30 (comment)

[aowss]

I think that there are 2 approaches:

• enrich the annotation to tell it which parameter should go in the builder constructor but this opens up the possibility of mistakes + this would generate only one additional constructor with the mentioned parameters

• build one builder constructor per record constructor. At the moment you build one no-arg constructor for the record's canonical constructor. You could then add one constructor per record constructor matching the signature.

so if the record was

public record Info(@NotNull String title, String summary, String description, URL termsOfService, Contact contact, License license, @NotNull String version) {

    public Info(@NotNull String title, @NotNull String version) {
        this(title, null, null, null, null, null, version);
    }

}

you would generate 2 constructors : InfoBuilder() and InfoBuilder(@NotNull String title, @NotNull String version)

But the following questions arise:

• should you even generate InfoBuilder()?
• what if the alternate record constructors do not mean mandatory parameters but alternative ones ?

for example this record:

public record License(@NotNull String name, String identifier, URL url) {

    public License {
        if (identifier != null && url != null) throw new IllegalArgumentException("A license can't have both an identifier and a url");
    }

    public License(@NotNull String name, String identifier) {
        this(name, identifier, null);
    }

    public License(@NotNull String name, URL url) {
        this(name, null, url);
    }

}

based on that i would go, if you still think it is worth it, go with the first approach but allowing multiple @RecordBuilder or @@RecordBuilder.Include annotations or allowing these annotations to take a list of mandatory parameters for each builder constructor to generate.

[Randgalt]

See #40 and #42