Wicket push reload support

When I look the cometd's instruction page here, it seems the the based source code do not support reload. As shown in the example, it requires a client side javascript code. But it was not written anywhere, as far as I saw.

I start supporting reload extension on my custom wicketstuff-push (see the post). Let's see the code.

public abstract class CometdAbstractBehavior extends AbstractDefaultAjaxBehavior {
    private static final long serialVersionUID = 1L;
 
    // FIXME: put this in application scope, we may have several webapp using
    // CometdBehavior in the same web container!
    private final static String cometdServletPath = getCometdServletPath();
  
    private static final ResourceReference COMETD =
        new CompressedResourceReference(CometdAbstractBehavior.class, "org/cometd.js");  
    private static final ResourceReference JQ_JSON2 =
        new CompressedResourceReference(CometdAbstractBehavior.class, "jquery/json2.js");
    private static final ResourceReference JQ_COMETD =
        new CompressedResourceReference(CometdAbstractBehavior.class, "jquery/jquery.cometd.js");

    private static final ResourceReference COMETD_RELOAD =
        new CompressedResourceReference(CometdAbstractBehavior.class, "org/cometd/ReloadExtension.js");
    private static final ResourceReference JQ_COOKIE =
        new CompressedResourceReference(CometdAbstractBehavior.class, "jquery/jquery.cookie.js");
    private static final ResourceReference JQ_COMETD_RELOAD =
        new CompressedResourceReference(CometdAbstractBehavior.class, "jquery/jquery.cometd-reload.js");

    @Override
    public void renderHead(final IHeaderResponse response) {
        super.renderHead(response);
        if (channelId == null) {
            throw new IllegalArgumentException("ChannelId in a CometdBehavior can not be null");
        }
        response.renderJavascriptReference(COMETD);
        response.renderJavascriptReference(JQ_JSON2);
        response.renderJavascriptReference(JQ_COMETD);

        response.renderJavascriptReference(COMETD_RELOAD);
        response.renderJavascriptReference(JQ_COOKIE);
        response.renderJavascriptReference(JQ_COMETD_RELOAD);
 
        response.renderJavascript(getInitCometdScript(), "initCometd");
        final String cometdInterceptorScript = getCometdInterceptorScript();
        if (cometdInterceptorScript != null) {
            response.renderJavascript(cometdInterceptorScript, "Interceptor"
                    + getBehaviorMarkupId());
        }
        response.renderJavascript(getSubscriberScript(), "Subscribe"
                + getBehaviorMarkupId());
    }

    protected final CharSequence getInitCometdScript() {
        return new PackagedTextTemplate(CometdBehavior.class, "CometdReloadInit.js").getString() +
            getConfigureCometdScript() + getHandshakeCometdScript(); 
    }

I add a javascript file. This code is written based on the reload example for jQuery (here).

/* handshake listener to report client IDs */
$.cometd.addListener("/meta/handshake", function(message)
{
    if (message.successful)
    {
        $('#previous').html(org.cometd.COOKIE.get('demoLastCometdID'));
        $('#current').html(message.clientId);
        org.cometd.COOKIE.set('demoLastCometdID', message.clientId, {
            'max-age': 300,
            path : '/',
            expires: new Date(new Date().getTime() + 300 * 1000)
        });
    }
    else
    {
        $('#previous').html('Handshake Failed');
        $('#current').html('Handshake Failed');
    }
});

/* Setup reload extension */
$(window).unload(function()
{
    $.cometd.reload();
});

Be care that this works on not only browser reloads, but also loading the same page with different parameters. It means, subscribing to the different channel also happens without handshake.