Springfox: Alternate type rules are not being applied

Question

My @EnableSwagger2 annotated class contains the following method:

@Bean
    public Docket myServiceApi() {
        return new Docket(DocumentationType.SWAGGER_2).groupName("My Service API").apiInfo(apiInfo()).select()
            .paths(PathSelectors.regex("/api.*")).build()
            .alternateTypeRules(
                newRule(
                    typeResolver.resolve(Map.class, String.class, Object.class),
                    typeResolver.resolve(InputExample.class)
                )
            )
            ;

    }

Where InputExample is a class that contains many different properties annotated with @ApiModelProperty.

The method in my REST controller looks like this:

@ApiOperation(
        value = "Do stuff",
        consumes = MediaType.APPLICATION_JSON_VALUE,
        produces = MediaType.APPLICATION_JSON_VALUE,
        response = SomeOutput.class
    )
    @RequestMapping(
        value = "/api/v1/stuff",
        method = RequestMethod.POST,
        consumes = {MediaType.APPLICATION_JSON_VALUE},
        produces = {MediaType.APPLICATION_JSON_VALUE}
    )
    @ApiResponses(
        value = {
            @ApiResponse(code = 200, message = "Service execution successful"),
            @ApiResponse(code = 400, message = "Bad input data"),
            @ApiResponse(code = 500, message = "An internal server error occurred"),
            @ApiResponse(code = 503, message = "The service is currently unavailable")
        }
    )
    public ResponseEntity<SomeOutput> doServiceStuff(
        HttpServletRequest request,
        @RequestBody Map<String, Object> inputContent
    ) throws
        ValidationException,
        ServiceUnavailableException,
        IOException,
        WorkflowDocumentProcessingException
    {
    ...
    }

Sadly, when I run my Service and open my endpoint on Swagger UI, all I see is:

What could this be caused by? How can I debug this?

P.S.: The rest of the @EnableSwagger2 - class does work.

Answer 1

There already seems to be an internal rule with the original type Map<String, Object> overriding whatever the developer adds to .alternateTypeRules().

The only way I could find to fix this is to create a class MyInputMap extends Map<String, Object> and use it in all endpoints in question, while also adjusting the type rule to:

newRule(
   typeResolver.resolve(MyInputMap.class),
   typeResolver.resolve(InputExample.class)
)