title: Catch a exception with interface.
body: <p>I have a question about the exception handling in PHP.</p>
  
  <p>I have a lot of exception those means the same: Couldn't found something. All those exception implements the interface (<em>not class</em>) <code>NotFoundException</code>.
  So to my question: It's possible to check if the exception implement the interface at the catch-block.
  I know i could change the NotFoundException-interface to a class but some exceptions extended already an other exception. (Example: <code>CategoryNotFoundException</code> extends <code>CategoryException</code> and implements <code>NotFoundException</code>).</p>
  
  <p>Why should I need this interface?
  When an page is showing and some exception which implements the interface will throw an Error404 should shown.
  Example:
      
  
  <pre><code>$userPage = $_GET["page"];
  try{
      showPage($userPage);
  } catch (){ //How to catch the `NotFoundException` interface?
      showPage("Error404");
  } catch (Exception $e){
      showPage("Error500"); //Something is wrong...
  }
  </code></pre>