title: How to get all class names inside a particular namespace?
body: <p>I want to get all classes inside a namespace. I have something like this:</p>
  
  <pre><code>#File: MyClass1.php
  namespace MyNamespace;
  
  class MyClass1() { ... }
  
  #File: MyClass2.php
  namespace MyNamespace;
  
  class MyClass2() { ... }
  
  #Any number of files and classes with MyNamespace may be specified.
  
  #File: ClassHandler.php
  namespace SomethingElse;
  use MyNamespace as Classes;
  
  class ClassHandler {
      public function getAllClasses() {
          // Here I want every classes declared inside MyNamespace.
      }
  }
  </code></pre>
  
  <p>I tried <code>get_declared_classes()</code> inside <code>getAllClasses()</code> but <code>MyClass1</code> and <code>MyClass2</code> were not in the list.</p>
  
  <p>How could I do that?</p>