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CometD Java Client Handshake

Java CometD Client API: Hanshake

To initiate the communication with the Bayeux server, you need to call


A typical usage is the following:

// Create (and eventually setup) Jetty's HttpClient
HttpClient httpClient = new HttpClient();
// Here setup Jetty's HttpClient, for example:
// httpClient.setMaxConnectionsPerAddress(2);

BayeuxClient client = new BayeuxClient(httpClient, "http://localhost:8080/cometd");
// Here setup the BayeuxClient, for example:
// client.addListener(new MessageListener() { ... });

The BayeuxClient is created with Jetty's HttpClient and with the URL that points to the Bayeux server.

When BayeuxClient.start() is called, the BayeuxClient will perform the handshake with the Bayeux server and then will establish the long poll connection, asynchronously.

Calling start() does not mean that you have completed the handshake with the server when start() returns.

To verify if the handshake is successful, you can add a MessageListener before calling BayeuxClient.start():

HttpClient httpClient = ...
BayeuxClient client = new BayeuxClient(httpClient, "http://localhost:8080/cometd");
client.addListener(new MessageListener() 
    public void deliver(Client from, Client to, Message message)
        if (Bayeux.META_HANDSHAKE.equals(message.getChannel())
            Boolean successful = message.get(Bayeux.SUCCESSFUL_FIELD);
            if (successful != null && successful)
                // Here handshake is successful