title: How do I document a Rest parameter providing another type (MyClass vs. String)?
body: <p>In Springfox I once used the following syntax to render a String parameter with a full model (<a href="https://github.com/springfox/springfox/issues/2523" rel="nofollow noreferrer">original Github issue</a>):</p>
  <pre><code>@PatchMapping(path=&quot;/{objId}&quot;)
  @ApiImplicitParams(@ApiImplicitParam(name=&quot;update&quot;, dataType=&quot;MyClass&quot;)) 
      public ApiResponse&lt;MyClass&gt; updateMyClassInst(@PathVariable String objId, @RequestBody String update) {
  </code></pre>
  <p>The reason for this formulation is that if I put <code>MyClass</code> as type for the request body I had no way to distinguish when a property has not been updated or when has been set to null, because both would be deserialized to a null field value.</p>
  <p>How do I do that with Springdoc?</p>