Differences between Pagebox Flavor

[thiruvasagamani]

What are the differences between PageBox flavors?

Since August 2000 we experiment different PageBox designs:


      In the first J2EE PageBox developed between August 2000 and May 2001 the PageBox agent was acting as a Web application container. There were pros and cons for this design. With this design it was possible to measure the Web application use. On the other hand we had to replicate functions already implemented by Application servers and this design requiring an extensive use of class loaders was not easily portable to other technologies like PHP or .NET.
   

      In parallel with the J2EE we developed an OSGi version. This Java standard specifies an application container with a smaller footprint than J2EE. We used the JES 2 environment for our developments. JES 2 allowed deploying applications on hardware like routers and appliances. These applications couldn't be standard J2EE Web applications but changes were limited.


      The PHP version was designed after the first J2EE version and developed between December 2001 and May 2002. It reused the convenient publish / subscribe mechanism, abandoned the JFC publisher in favor of a simple publication page and introduced the use of Web services.
 

      The .NET version was designed after the PHP version and developed between March and August 2002. It introduced an API allowing a Web application instance to find its clones deployed from the same Repository, a Grid API facilitating the development of distributed applications, the Web applications deployed from the same Repository acting as computation nodes, an Active Naming allowing finding the best instance for serving a request and a coordinator for control to control communication.

This experience allowed designing a new J2EE version, called PageBox for Java whose development started in September 2002 and is still ongoing. This version implements the most effective functions found in the previous versions and address their shortcomings:


      Deployment with relays for a fast deployment on many agents
 

     Delta deployment to only send the changes in case of application update


      Installation step: The Web application can provide an installation class for instance to populate a database
 
Application server installation:

the PageBox agent installs the Web application. The application is usable as soon as the installation was completed.
 

      Token ring API: Web applications can send messages to each other and broadcast messages. This implementation minimizes the number of messages and simplifies data replication.
 
      An improved Active Naming that uses the Token API
 
      A better security: the agent administrator can grant deployment rights to publishers and repositories.

      Extensibility: the administrators can choose the network transport layer or define their own transport layer. They can also create extensions that Web applications can use to access to normally forbidden resources, for instance using native code.

As a consequence the different versions are not interoperable and don't have the same functions.

We froze all versions except PageBox for Java to concentrate our efforts on this version that should move to beta status in the coming months. This PageBox for Java could also be augmented for a better support of controls in the .NET version way.