Clojure CometD client example

cometd_client.clj

(ns test.cometd-client
  (:import (org.cometd.bayeux.client ClientSessionChannel$MessageListener)
           (org.cometd.client BayeuxClient BayeuxClient$State)
           (org.cometd.client.transport ClientTransport LongPollingTransport)
           (org.eclipse.jetty.client HttpClient)))

(def channel-name "/my-channel")

(def client-url "http://localhost:8080/cometd")

(defn call-with [message]
  (let [received-message (promise)
        listener (proxy [ClientSessionChannel$MessageListener] []
                   (onMessage [channel message-map]
                     (deliver received-message (get (into {} message-map) "data"))))
        http-client (HttpClient.)
        http-transport (LongPollingTransport. nil http-client)
        bayeux-client (BayeuxClient. client-url http-transport (make-array ClientTransport 0))]
    (try
      (do
        (.start http-client)
        (.. bayeux-client (getChannel channel-name) (addListener listener))
        (.handshake bayeux-client)
        (.waitFor bayeux-client 5000 BayeuxClient$State/CONNECTED (make-array BayeuxClient$State 0))
        (.. bayeux-client (getChannel channel-name) (publish (java.util.HashMap. {"data" message})))
        @received-message)
      (finally        
        (.disconnect bayeux-client 1000)))))