In Jersey, how to return an object with 400 response code different than the 200 response object - rest

Question

I am new to Jersey and to REST in general, so this might be a stupid question....
In my code, I send a request (TemplateValidationRequest) to try to validate an object. If the object fails to validate, I want to return a String. How do I do this?
In the second code snippet at the bottom, you can see that I'm looking for TemplateValidationResponse object. How can I change my code so that:
I can return a string, and
I can get a String instead of a TemplateValidationResponse object.
Is this possible?
#POST
#Path("validate/modelTemplate")
#Produces({MediaType.APPLICATION_JSON})
#Consumes({MediaType.APPLICATION_JSON})
#Operation(
summary = "Convert model template to AMBOS interaction model and validate the result",
tags = { BLUEPRINTS_TAG },
requestBody = #RequestBody(
content = #Content(
schema = #Schema(
implementation = TemplateValidationRequest.class
)
)
),
responses = {
#ApiResponse(
responseCode = "200",
description = "Success.",
content = #Content(
schema = #Schema(
implementation = TemplateValidationResponse.class
)
)
),
#ApiResponse(
responseCode = "400",
description = "Failure",
content = #Content(
schema = #Schema(
implementation = String.class
)
)
)
}
)
#CustomerIdentityRequired
#AcceptsLanguageRequired
#AAA(serviceName = SERVICE_NAME, operationName = BLUEPRINTS_GET)
ModelTemplateValidationResponse validateModelTemplate(TemplateValidationRequest);
 
fun validateModelTemplate(modelTemplate: InteractionModel,
sampleData: Map<String, Any>): TemplateValidationResponse {
val request = TemplateValidationRequest()
request.modelTemplate = modelTemplate
request.sampleData = sampleData
return temp.validateModelTemplate(request)//this is where I call the above code
//If this request fails and results in a 400 error, I want to get a String
}

Answer 1

What about something like:
public Class YourResponse {
private boolean isError;
private String setThisWhenThereIsError;
private YourObject setThisWhen200;
}