In ESB How to check if a key exists in json response
<p>I'm new to ESB proxy services, 
I'm getting JSON response from a Google service, I need to check if a specific key exists in the response, i.e. In the following json,<br>
<code>{
  "kind":"$$$$",
  "totalItems":0
  }</code>  </p>

<p>I need to check if totalItems exists in the response and I want to filter this in proxy-service itself.
Thanks in advance</p>