What is best practice on handling duplicate method calls?
<p>Let's say I have a class loader I want to register.</p>

<pre><code>$loader = new ClassLoader;

$loader-&gt;register();
</code></pre>

<p>When the method <code>register()</code> is called a second time, should I:</p>

<ol>
<li>Throw an exception stating that the class loader has already been registered</li>
<li>Silently fail</li>
<li>Return a boolean status</li>
</ol>

<p>If I were to go with option #1, I would also provide a <code>isRegistered()</code> method offer the opportunity for some checking before it is called a second time.</p>

<p>What is the best way of handling this scenario?</p>

<p>Are there any other, better options?</p>
