title: Bean validation after setter?
body: <p>I want to validate the trimmed string length, like:</p>
  
  <pre><code>@Size(min = 5, max = 20, message = "Please enter a valid username (5-20 characters)")
  String userName;
  </code></pre>
  
  <p>Given user name <code>foo</code> (6 chars), it will be trimmed to <code>foo</code> (3 chars) in the setter method, however, validate against the raw input seems a bit of useless.</p>