As Okke stated earlier, Duncan Mills has made a visit to the Netherlands to speak on an event called Guru4Pro. Guru4Pro is a series of presentations given by knowledgable guru’s. The first of these presentations was given by Duncan Mills of Oracle. Duncan has been working in the field for 18 years in total, of which 14 years for Oracle. Duncan started on the support department but quickly switched to product development. Currently he is developing the ADF framework, the framework we use for application development.
The presentation was called ‘The rise (and rise) of the meta-framework’. The presentation gave a clear view into the world of frameworks and meta-frameworks. Duncan first started by explaining what a framework exactly is. His view is that every (competent) developer will build there own convenience libraries to make their own life easier. I personally like the comment “If your developers aren’t constantly developing their own libraries to make their job easier, you should fire them and hire others.” It make the point clear that deep down everybody should be thinking about extracting the ‘dumb’ and ‘easy’ stuff and letting libraries do that for you. However a library, or a set of libraries isn’t a framework…
A framework is a complete solution for a specific problem, a point solution. Good examples are Toplink, Hibernate, Struts, JSF, EJB, Spring, etcetera. Frameworks should be applicable for more than one solution, they should be flexible enough to solve the problem every time for each application you make. A good framework at least.
Duncan further stressed the criteria he feels a (good) framework should fill (i list here only a few):
- Coverage and depth: a framework should do everything you need. If it won’t (say your persistence framework cannot do updates) you won’t use it
- Documentation & User guidance: a good framework should just give you a set of API’s. If the framework is to succeed you need to explain the framework in documentation and it should provide guidance in the way to solve problems, the right way
- Infrastructure not generation: a framework provides the plumbing, it does not generate code. If you just generate code you’ll have problems during maintenance. Frameworks abstract and solve the problems
- Pluggability: the meta-framework should work with different frameworks. And it should work exactly the same
- And last but not least ‘a cool name’: has anybody heard of the Oracle MVC framework? No, but Spring rings bells. Spring is a cool name
After defining what a framework was, Duncan gave the term ‘meta-framework’ a meaning. A meta-framework is a framework that combines all kinds of frameworks to provide a complete solution. The meta-framework should integrate the frameworks and make sure they work together correctly. The developer using the meta-framework should be able to do things in a consistent way without bothering about the underlying frameworks.
Duncan gave an example using the Oracle ADF framework (the new one based on JSF) and Oracle JDeveloper 10.1.3. First he wizarded two kinds of datasources together. Nobody will be to overly impressed by an IDE that can give you a wizard that can generate your persistence layer. However he created a persistance layer based on Toplink and EJB 3.0 session beans, next to that he created another persistance layer based on Oracle Business Components. Next we went on to the UI. Duncan showed that using the meta-framework and abstractions that Oracle ADF gives the developer to possibility of using data sources as just a source of data without thinking about the implementation. He could drag-and-drop the Toplink and EJB based data on a JSF page the same way as the Oracle BC based data. After that he showed how to integrate those two sets of data and synchronize them. You could now browse the department data (via the Toplink and session EJB) and see the relevant employee list (via Oracle BC) and without much ado those two different data sources were combined. Personally i found this a really good demo, it was pleasing to see something else than the usual slick sales manager click-through. Duncan later told me he only thought up this demo a few hours before the presentation; he also thought it was good the show something closer to reality.
After the Oracle ADF demo the presentation went on over meta-frameworks. The only other framework that comes close to meta-frameworkness was Spring. Both Oracle ADF and Spring come close, but neither are there completely yet. Both meta-frameworks revolve around their key-ability to glue frameworks together. Oracle ADF used the ADF Model Binding layer and Spring uses the bean factory. Spring for example has better security support than Oracle ADF, but Oracle ADF has better tool support.
The last part of the presentation was about trends that are comming. The latest trend is that the standards are behaving differently and comming up to par with proprietary (not in the sense of ownership, but in the sense that it isn’t the standard) frameworks. JSF has come to replace Struts. EJB 3.0 is comming for Toplink and Hibernate. Duncan explained that when the standards are getting better, the frameworks will be getting thinner and thinner and finally will fade as a framework a become an implementation of the standard. Meta-frameworks are rising and will rise in the future.
One of the most enlightning things were the challenges Duncan named. He said that meta-frameworks have a few (few?) challenges ahead. One of the challenges is debugging. Debugging should be abstracted just as development is. Why should you be thrown in the framework source code when you only created a XML to configure something? You shouldn’t, Duncan formulated this very eloquently by stateing (cannot produce the exact quote but it was something like) ‘Frameworks have recognized the debugger, debuggers have yet to return the favour’. Dbuggers will have to become ’smarter’ or maintenance will be problematic.
Another challenge that we developer and i myself am constantly struggling with is State Management. At the moment the only problem i have with state management is the fact that i have a heck of a problem because users want to use that ‘back button’ in their browser. They also want to use the ‘Open in new window/tab’ functionality and have the application react correctly. With our applications it isn’t working. Fortunately the meta-framework developer has also recognized this problem and is working on it. This was one of my most pleasant surprises: They (they is Oracle here) actually have a (good) clue about the problems in facing when using their product (framework) and they are working on it!
As all presentations end, this one was also concluded with a refreshing drink and talk in the internal bar at LogicaCMG (yes, the cafeteria actually also has a small bar. Big plus for any employer)
A few collegaes and i also had the pleasure to meet Duncan before the presentation and the next day to talk about all sorts of stuff. We could talk freely about the pro’s and cons of the Oracle ADF framework and hear what Oracle is doing with it. Duncan is very knowledgable about the framework and is a real pleasure talking about it. You can really fell that he has a passion for the work he is doing and that he believes this is the right way to go.
I would like to thank Duncan again for his presentation and would recommend everybody to attent a presentation of Duncan if they can.
You can download the presentation here. It contains the slides including comments written by Duncan to explain the story fully.
PS. [shameless plug]Look at the Guru4Pro presentations. They are free to attend, you’ll like them.[/plug]
Links
Duncan Mills’s Weblog
The slides and comments of the presentation given by Duncan
Guru4Pro
