Intellectual Frameworks for Classifying Ajax Frameworks

Dietrich Kappe, Friday, August 18, 2006 @ 9:00 am

Who knew that a simple architectural principle like AJAX (Asynchronous Javascript and XML) would cause so much trouble? The trouble I'm having at the moment is classifying different Ajax frameworks in ways that make sense to developers, designers and business people all at once.

There are a number of people who have pondered the Ajax framework classification question and are very much worth reading:

• Dion Hinchcliffe has wrestled some with building an intellectual framework for classifying Ajax frameworks and approaches. He divides them roughly into the full lifecycle Atlas, the declarative Laszlo and Backbase, and the client-side Dojo.
• Michael Mahemoff on his excellent Ajax Patterns Wiki, has taken it upon himself to produce a good collection of Ajax frameworks, somewhat categorized, and the beginnings of a framework comparison martix. His take seems to be client, server and hybrid frameworks.
• Daniel Zeiss has a comparison matrix just for .NET Ajax frameworks. One way he classifies the frameworks is by those that have a multi-page versus a single-page interface.
• The Midnight Coders have a feature matrix comparing their product WebORB with DWR, Ajax.NET and Sajax. It's the usual feature matrix with check boxes in all of WebORB's rows.
• I, myself, have emphasized the benefits of abstraction provided by the server-side frameworks like Echo2, versus the frameworks that expose too much of the browser details.

All of these different takes on comparing Ajax frameworks reminds me of a professor I had at the University of Chicago, McKim Marriot. He was a Social Anthropologist and taught us about South Asian culture. He emphasized to us that the answer to any question about ancient India depended on your viewpoint or context. My memory is failing me a little bit, but as I recall, there were three basic principles -- Dharma, Karma and Artha -- through which everything was filtered. He had a grad student make him a big plexiglass box with each of the three pairs of facing sides tinted a different primary color -- red, green and blue, as I recall. Depending on which way you looked through the box, you got different color combinations. By the time I took his class, the colors had faded and the box was scuffed and suffering from some sort of inner condensation problem.

Still, he would twirl it around in class, mumbling about perspective, context and viewpoint. His way of thinking is very similar to the ideas in UML and the various OOAD approaches, where each diagram or artifact gives a different view or perspective into a system -- domain, design, behavioral, deployment, physical, etc.

Looking at the above different comparisons, we can extract a few perspectives and add our own.

• Architectural - n-Tier webapp, desktop GUI-style abstraction on the server, SOA-style client orchestrator of services, browser extension cross-site apps, etc.
• UI Style - enhanced page based versus single page.
• Language - Java, C#, Javascript, PHP, Ruby, etc., both on the server side and for generating Javascript.
• Component - Client engines, Server engines, Client Plugin, Widgets, Transport Protocols, etc.
• Feature - is it themeable, does it integrate with db, does it degrade gracefully, what kind of effects does it have, etc.
• SDLC - do we develop webapps the same way as before, or do we change?
• Tools & Methods - IDE support, debugging support, etc.
• Platform - pure browser, hybrid Flash/Javascript, etc.
• Application Framework - does it provide all of the things, in an Ajax way, that we've come to expect from other web frameworks: authentication, database persistence, workflow, etc.?

Seen through this prism, some packages we've previously thought of as frameworks are not really frameworks at all. For example, seen through the SOA (service oriented architecture) perspective of Javascript apps running in the browser as orchestrators of web services, Tibco GI is a framework. Seen through a client/server or n-tier webapp architecture perspective, Tibco GI isn't a framework but only a part of a larger solution.

What I've realized over the last few months is that this simple architectural idea of Ajax has opened up a whole new world of possibilities when it comes to writing web applications, with the simple n-tier app giving way to a number of new approaches. Anyhow, this is all still percolating in my brain and is not in a ready state by any means.

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Comments: 1 so far

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1. 

   As we did before? Most big business I know of didn’t know what they were doing, they just did it If anything, Ajax inspires a stronger gui mindset, which in my mind might help leverage talented developers from the desktop paradigm to help build the next generation of webapps.

   I like Echo2 for specifically that reason; the intent and design is painfully clear and simple, it really makes it a strong foundation for applicaion development.

   Comment by Ivan, Saturday, August 19, 2006 @ 8:02 pm

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