DWRリクエストでフィルタでセッションを検証

public class DwrFilter implements AjaxFilter {
	private static final Log logger = LogFactory.getLog(DwrFilter.class);
	public Object doFilter(Object object, Method method, Object[] arr,
			AjaxFilterChain chain) throws Exception {
		
		//DWR session 
		HttpServletRequest request = WebContextFactory.get().getHttpServletRequest();
		HttpSession session = request.getSession();
		SessionAgentTool.setSession(new SessionContext(session));
		
		// 
		String methodName = method.getName();
		logger.info(" DWR ：" + methodName);

		Object obj = chain.doFilter(object, method, arr);
		logger.info("DWR  " + method.getName() + "  ");
		return obj;
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" 
      "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
    <allow>
        ......
        <filter class="com.wingon.core.filter.DwrFilter"></filter>
    </allow>
</dwr>