title: Avoiding hardcoded class name with usort
body: <p>I am implementing a sorting solution in a static method. Basically, I have:</p>
  
  <ol>
  <li>A static class (<code>Xbanners</code>)</li>
  <li>A static property (<code>Xbanners::$banners</code>) in this class holding an array of objects</li>
  <li>A static method that sorts this array of objects depending on one parameter stored as a property on those objects ( <code>Xbanners::$banners[0]-&gt;priority</code> ).</li>
  </ol>
  
  <p>I just use <a href="http://php.net/manual/en/function.usort.php" rel="nofollow">usort()</a> to call the sorting method, but I have to hardcode the name of my class. How could I avoid this? </p>
  
  <pre><code>usort(self::$banners, 'Xbanners::' . $sortingMethod);
  </code></pre>