Mule-Throw error if the query parameter is not available
<p>I need to throw an exception if the query parameter say "<strong>requestId</strong>" is not present in request URL. </p>

<p>The URL looks like this: <code>my.server.com?requestId=123&amp;age=26</code></p>

<p>Here I'm logging the <strong>requestId</strong> in message property like this:</p>

<pre><code>&lt;message-properties-transformer scope="session" doc:name="Adding requestId"&gt;
    &lt;add-message-property key="requestId" value="#[message.inboundProperties.'http.query.params'.requestId]"/&gt;
&lt;/message-properties-transformer&gt;
</code></pre>

<p>If the URL does not contain the requestId it will be null. But in this case I want to do a check for <strong>requestId</strong> whether it is present or not.
Then </p>