Add custom annotation when generate backend code with swagger codegen

Question

I'm trying to generate sever code with swagger codegen. In my model have some custom annotation like @Currency

@Target({ METHOD, FIELD, ANNOTATION_TYPE, PARAMETER })
@Retention(RUNTIME)
@Size(min = 3, max = 3)
@Pattern(regexp=TwintPattern.CURRENCY)
@Constraint(validatedBy = {})
@Documented
public @interface Currency {
    String message() default "{javax.validation.constraints.Size.message}";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};
}

Can we let swagger know and generate it also in model class?

You can't do that. It's one of the biggest problems with all of the existing Swagger/OpenAPI generators. — chrylis -cautiouslyoptimistic-, Jan 13 '20 at 08:09
I see that swagger has custom template, I see that we can change name but not know that we can add in template to do this or not ? — Park Jay, Jan 13 '20 at 08:57

score 2 · Answer 1 · answered Apr 19 '23 at 06:00

Starting from OpenAPI Generators version 6.0.0, for Java language, you can use x-class-extra-annotation out of the box without any customization to the mustache templates.

In your example, if you have a Payment object in your OpenAPI specs and you'd like to use the Currency annotation, it would look like this:

Payment:
  type: object
  x-class-extra-annotation: "@fully.qualified.name.of.Currency(message = \"This is a message to override the default one, in case it's required\")"
  properties:
     # ...

The generated Payment Pojo will look like this:

@fully.qualified.name.of.Currency(message = "This is a message to override the default one, in case it's required")
public class Payment {
   // ... fields, setters, and getters as usual
}

Reference:

https://github.com/OpenAPITools/openapi-generator/pull/11775

kairius · Answer 2 · 2021-09-29T11:17:04.163

It's possible by using custom templates.

E.g.:

Add extension to Open Api spec model:

Person:
  type: object
  x-validations: "@ValidPerson"
  ...

Add fragment to pojo.mustache:

{{#useBeanValidation}}
 {{#vendorExtensions.x-validations}}
  {{vendorExtensions.x-validations}}
 {{/vendorExtensions.x-validations}}
{{/useBeanValidation}}

Or alternatively, if you don't have an option to add something to the spec, you can implement model post processor and add vendor extension values dynamically.

Vitaly Roslov · Answer 3 · 2022-01-11T19:46:14.687

0

I've been stuck with the similar problem and as the result made an example for swagger-codegen-cli v3 and gradle: Here it is

This might not be exactly what you wanted. The annotations are defined in java code and used by the generated model code.

It is an elaboration of kairus'es method

I've started with this article - this method also works, but making a new language proved to be unnecessary.

edited Jan 11 '22 at 19:46

answered Jan 11 '22 at 19:37

Vitaly Roslov

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Add custom annotation when generate backend code with swagger codegen

3 Answers3