title: allowableValues From a File
body: <p>I might be going about this the wrong way, but is there a way to populate the allowableValues string from a json file?  </p>
  
  <p>Every method I've tried in reading from a file/json ends up with me having to call a method like toString(), resulting in a non-constant result.  Swagger won't allow non-constant allowableValues, but it seems silly to me that I would have to manually update this list programmatically rather than in an external file in order to add to this list.  </p>
  
  <p>I suspect there isn't a compile time strategy that would work here, but just thought I would ask.  Any suggestions would be greatly appreciated! </p>
  
  <pre><code>@ApiOperation(value = "Retrieve information")
  @RequestMapping(value={"dothis/thing"}, method=RequestMethod.POST, produces=MediaType.APPLICATION_JSON_VALUE)
  @Produces({"application/json", "application/xml"})
  public JsonNode applicationList(HttpServletRequest request,
                                         @ApiParam(name="input_name", value="Input Name", allowableValues = LIST_OF_VALUES) @RequestParam (required = false) String input_name) throws GeneralException {
  </code></pre>