title: Disable JButton when not logged in
body: <p>I am creating a mini project.  My project is a library management system.</p>
  
  <p><img src="https://i.stack.imgur.com/Toigz.png" alt="This is my login page"></p>
  
  <p>How can I disable the issue button in advanced search if I am logged in by clicking <code>Anonymus</code>?
  Or how can I enable the issue button if logged in as administrator?</p>
  
  <p><img src="https://i.stack.imgur.com/X5yVg.png" alt="this is my advance search for books"></p>