title: Getting username in PasswordEncoder
body: <p>I created my own authentication provider for my spring application, on which I specified the <code>org.springframework.security.crypto.password.PasswordEncoder</code>. I have my users stored in the database with their encrypted passwords (after a database algorithm). For being able to make the authentication, I would need to have access from the <code>org.springframework.security.crypto.password.PasswordEncoder</code> class to the username that is sent for authentication. Can anyone guide me how can I do this? Or is there any other approach?</p>
  
  <p>N.B. I'm using <em>SpringSecurity</em> 3.2.</p>