swagger 2.0 not validating enum in header

Question

I am working on a project that uses Swagger 2.0 to generate an API interface which is then implemented in production code. There is a problem with a parameter that comes from the header.

There are 2 desired behaviors -

1. If a value is provided and does not match the enum, it should throw an error
2. If no value is provided, it should be given the default value of 'English'

Here is the code -

parameters:
  language:
    in: header
    name: language
    description: language the request will be processed in
    type: string
    default: English
    enum: [English, Spanish, German, French]
    required: false

However, the API accepts any value and does not provide a default value.

The generated code does not give any hint that it should be an enum. It does show the default value but did not provide it when I performed an integration test.

@ApiParam(value = "language the request will be processed in" , defaultValue="English") @RequestHeader(value="language", required=false) String language);

I found other similiar questions on here but no answers - Swagger does not validate enum query parameter