[SWIFT4] Response decoder doesn't work with primitives types

Swagger-codegen version

2.4.0-SNAPSHOT

Description

When decoding the response in Swift4, it's work perfectly with JSON object, String, File (data) but it does not work with primitives type like boolean (just work with String)

To decode the response, a builder is used in "AlamofireDecodableRequestBuilder" class. This builder is AlamofireRequestBuilder where "T" is the type of response object.
In this class, there is a switch/case with the following types : String/Void/Data/default.
When the response type is Boolean or Integer for exemple, it runs in the default case.
But in this case, we are waiting for an object in JSON format. (see line CodableHelper.decode).
An error appears because decoder is waiting for JSON with {} tag.

In my rest API I have this for exemple :

@PUT
@SecuredToken
@Path("/test")
@ApiOperation(value = "test", response = Boolean.class)
@ApiResponses(value = {@ApiResponse(code = 200, message = "", response = Boolean.class)})
public Response test() {
	return Response.ok().entity(true).build();
}

"/test" : {
      "put" : {
        "tags" : [ "XXX" ],
        "summary" : "test",
        "description" : "",
        "operationId" : "test",
        "consumes" : [ "application/json" ],
        "produces" : [ "application/json" ], //i have test with text plain too
        "parameters" : [ ],
        "responses" : {
          "200" : {
            "description" : "",
            "schema" : {
              "type" : "boolean"
            }
          }
        }
      }
    }

Suggest a fix/enhancement

In switch default case, see if the type is primitive, and only cast in this case.

Start at the Swift4 AlamofireDecodableRequestBuilder entry point and inspect how CodableHelper.decode handles response types. Reproduce the issue with Boolean and Integer responses, then verify that primitive JSON responses decode successfully alongside the existing object, String, Void, and Data cases.