title: getting information about the principal
body: <p>I have several methods for a restful webservice with this signature</p>
  
  <pre><code>public @ResponseBody SomeObject someMethodSignature(Principal principal){
  </code></pre>
  
  <p>given that it's legacy code, is there a way to get other information from principal (<code>Principal</code> is an interface from <code>java.security</code> with only one useful method <code>getName()</code>) other than the name without the need to pass anything else to the method as parameter? Like permissions and stuff like that?</p>
  
  <p>thanks</p>