Super Size EMF Fast Food Demo: Tracking your live-models (Part 1)

Last week we submitted a talk at Eclipse Con 2010 “Add Complex Event Processing to your EMF models: Super Size models Fast food demo“. This is a good opportunity for explaining the concepts and architecture exposed in the talk. Actually that’s a good continuation of the last post. Indeed, we saw the M2M principles and the reasons why we needed transformation support and tracking of modifications from live-models.  Today we  put all those things in practise and dive into a real application example with live models, going further we use Complex Event Processing for injecting “intelligence” in the application.

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Model transformations in new design approaches

Today we dive into a technical and theoretical track on the model transformation. In this post we investigate the existing techniques in Eclipse M2M in order to transform models, going further we replace them in the live-Model context and define what do we need to design such applications. We also present the live Weaver developed by our colleague Olivier Moises, which enables to track model changes. We will see how this kind of framework can be used in live transformation.

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Atmoshpere & Asynchronous Servlet

Last week, I was at Devoxx and I attended to a speech of JF Arcan, the head architect of the Atmoshpere framework [1]. While the new coming Servlet 3.0 Async provides

  • Method to suspend a response, HttpServletRequest.startAsync()
  • Method to resume a response: AsyncContext.complete()

Atmosphere offers:

  • Annotation to suspend: @Suspend
  • Annotation or resume: @Resume
  • Annotation to broadcast (or push) events to the set of suspended responses: @Broadcast
  • Annotation to filter and serialize broadcasted events using BroadcasterFilter

In [2], JF Arcand demonstrates how Atmosphere can be used to suspend a request but also broadcasting a message to all suspended threads. Atmoshpere defines the notion of broadcastable and topics.

A topic is a kind a message channel on which broadcastable servlet can listen. Later on, any other client can broadcast messages on this topic and then reaching all suspended-threads.

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