Subscribe to topic only when a condition is met

[aozaversa]

I am trying to implement websockets using jersey. I have a method subscribe in my AtmosphereServlet which returns SuspendResponse.SuspendResponseBuilder().addListener().build().

I want to subscribe to the topic only when a certain condition is met. Where do I write this condition. How do I reject the handshake. If I should write it in my subscribe method, how do I implement it?