Welcome!

Machine Learning Authors: Yeshim Deniz, Pat Romanski, Liz McMillan, Elizabeth White, Corey Roth

Related Topics: Java IoT

Java IoT: Article

Integrating AJAX with the JMX Notification Framework

Opposite Ends of the Systems Management Stack

Each step is described in detail below.

Register MBeans and MBean Listeners
On each J2EE server instance, two start-up classes are run at server start-up:

  • ManagementStartup: Registers the UserWeb MBean in the local MBean server. Startup class parameters include default settings of the alert status, as well as the MBean name and MBean class. For example:

    <StartupClass
       Arguments="ServerName=admin,
         MBeanName=ExampleApp:Name=UserWeb,
         MBeanClass=com.grahamh.management.userWeb.UserWeb"
         ClassName="com.grahamh.management.startup.ManagementStartup"
       FailureIsFatal="true" Name="UserWEB" Notes=""
       Targets="admin,OLTPCluster"/>

  • MbeanRegistrations: Used to register a Singleton POJO, ManagementListener, with the UserWeb MBean on the administration server.

    A javax.management.NotificationFilterSupport object is used to list the notification types that the UserWeb MBean will generate and the listener will receive:

    // MbeanRegistrations.java
    MBeanHelperFactory.getWebHelper().registerListener();

    // UserWebMbeanListener.java
    public void registerListener() throws UserWebException{

    try {
    // get listener and filter
    ManagementListener listener = MBeanHelperFactory.getListener();
    NotificationFilterSupport filter = listener.getSupportedEvents();

    // get admin mbean server;
    //register the listener and filter with the UserWeb MBean
    RemoteMBeanServer rmbs = getAdminMbeanServer();
    rmbs.addNotificationListener
    ("ExampleApp:Name=UserWeb", listener, filter, null);
    }
    catch (Exception e) {
    throw new UserWebException
    ("Unable to registerListener: "+ e.getMessage(), e);
    }
    }

    The listener.getSupportedEvents() method returns the following filter:

    NotificationFilterSupport filter = new NotificationFilterSupport();
    filter.enableType("alert.broadcast");

When ManagementListener is run at server start-up, a connection is made to the MBean server on the (remote) administration server and the (local) ManagementListener is registered as a listener on events generated by the UserWeb MBean, with a filter set to "alert.broadcast" event types.

Because the ManagementListener implements Weblogic.management.RemoteNotificationListener, it can get JMX notifications that are generated in either the local JVM or a remote JVM; in this case, generated in the remote administration server JVM.

Broadcast Admin MBean properties
The administration and managed UserWeb MBeans can be set independently, giving any one J2EE server a localized AJAX response. However, a general Operations, Administration & Support (OA&M) support pattern would set the admin MBean properties and then broadcast these properties to the MBeans on the remote application servers, using the Notification model, for subsequent AJAX retrieval.

Because the UserWeb MBean is based on ApplicationMBean, which extends javax.management.NotificationBroadcasterSupport, the infrastructure is in place for the UserWeb MBean to notify all listeners. Hence, the administrator sets the relevant MBean properties (using the HTMLAdaptor) and clicks BroadcastState (see Figure 2).

Consequently, the UserWeb.broadcastState()method is executed, which notifies all listeners synchronously with the state of the admin MBean:

public void broadcastState() throws Exception {
try {
Notification n = new Notification
("alert.broadcast", "ExampleApp:Name=UserWeb", 0);
n.setUserData(new UserWeb(this));
this.sendNotification(n);
}
catch (Exception e) {
throw e;
}
}

Because the data is serialized over the network, the non-transient object graph must be serializable.

Receive Notification of MBean Props via Listener
The event listener is the ManagementListener Singleton. The JMX Notification framework on the administration server makes a remote call to the ManagementListener handleNotification() method in each listener on each of the OLTP cluster JVMs, which registered on server start-up:

public void handleNotification(Notification notification, Object handback) {
System.out.println("Received alert: " + notification.getType());

// get event userdata from notification
Object userData = notification.getUserData();

if (userData instanceof UserWeb) {
// comes from destin8 Web
UserWeb WebVo = (UserWeb)userData;
UserWebMBeanHelper helper = MBeanHelperFactory.getWebHelper();

// get from value object and set into local MBean using
MBeanHelper
helper.setAlertMessage(WebVo.getAlertMessage());
helper.setAlertStatus(WebVo.getAlertStatus());
helper.setCallBack(WebVo.getCallBack());
helper.setRefreshAlertStatus(WebVo.getRefreshAlertStatus());
}
}

The 'master' UserWeb data is set into the local User-Web MBean via its MBean helper. Consequently each managed server is updated with the master UserWeb state.

That's as far as the JMX elements need to go.

AJAX Request of Management State
The browser client is AJAX-enabled as follows:

  • main.jsp - instrumented JSP page that checks the (JMX) alert status and polls the server for alerts. It includes admin.js
  • admin.js - JavaScript utilities that use XMLHttpRequest to poll the server for the management state, parse the XML response, and repaint the 'status' area of the screen
JavaScript (described below) is included in main.jsp as follows:

<script type="text/javascript" src="./js/admin.js" ></script>

Rather than poll continuously, we will only poll if alerting is enabled. We use the UserWebMBeanHelper to check this status. If enabled, the JavaScript function initAdmin() is invoked when the page loads:

<%
if (MBeanHelperFactory.getWebHelper().isAlertEnabled()) {
%>
<body bgcolor="#F4FFE4" onload="initAdmin();">
<%
} else {
%>
<body bgcolor="#F4FFE4">
<%
}
%>

More Stories By Graham P. Harrison

Previously a Senior Consultant with BEA, Graham is the author of Dynamic Web Programming using Java (Prentice Hall, 2000) in addition to a number of articles for the Java Developers Journal and IBM DeveloperWorks. He has a focus on Enterprise Architecture, Performance Tuning and Capacity Planning

Comments (7) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Mark 09/29/06 02:36:10 PM EDT

I would like to get a copy of the source code that accompanies this article. Please send it to elihusmails[at]gmail[dot]com

thank you.

Mark 09/29/06 02:29:13 PM EDT

I would like to get a copy of the source code that accompanies this article. Please send it to elihusmails[at]gmail[dot]com

thank you.

hong li 05/29/06 09:40:54 AM EDT

My email address is : [email protected]

hong li 05/29/06 09:38:44 AM EDT

Could you please forward the whole source code to me which show those code to implement function of notification system useing Ajax and JMX?

Thanks!

Pete 02/05/06 09:10:28 AM EST

Great article when you want to understand an integration point between AJAX and wider J2EE space.

Bill Ley 01/31/06 07:44:42 PM EST

This is an awful article.

?? ???? 12/22/05 09:12:21 PM EST

Trackback Added: AJAX with the JMX Notification Framework; blockquote>Integrating AJAX with the JMX Notifica

CloudEXPO Stories
Poor data quality and analytics drive down business value. In fact, Gartner estimated that the average financial impact of poor data quality on organizations is $9.7 million per year. But bad data is much more than a cost center. By eroding trust in information, analytics and the business decisions based on these, it is a serious impediment to digital transformation.
In an era of historic innovation fueled by unprecedented access to data and technology, the low cost and risk of entering new markets has leveled the playing field for business. Today, any ambitious innovator can easily introduce a new application or product that can reinvent business models and transform the client experience. In their Day 2 Keynote at 19th Cloud Expo, Mercer Rowe, IBM Vice President of Strategic Alliances, and Raejeanne Skillern, Intel Vice President of Data Center Group and GM, discussed how clients in this new era of innovation can apply data, technology, plus human ingenuity to springboard to advance new business value and opportunities.
With more than 30 Kubernetes solutions in the marketplace, it's tempting to think Kubernetes and the vendor ecosystem has solved the problem of operationalizing containers at scale or of automatically managing the elasticity of the underlying infrastructure that these solutions need to be truly scalable. Far from it. There are at least six major pain points that companies experience when they try to deploy and run Kubernetes in their complex environments. In this presentation, the speaker will detail these pain points and explain how cloud can address them.
Discussions of cloud computing have evolved in recent years from a focus on specific types of cloud, to a world of hybrid cloud, and to a world dominated by the APIs that make today's multi-cloud environments and hybrid clouds possible. In this Power Panel at 17th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists addressed the importance of customers being able to use the specific technologies they need, through environments and ecosystems that expose their APIs to make true change and transformation possible.
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to the new world.