Tuesday, September 16, 2008

Why should I eat dog food?

I was reading this interesting article that my friend Mirco Casoni wrote on Mokabyte. He basically reviews and criticize the idea of framework and the unfortunate implementations of the framework concept he happened to see as a consultant (implementations which I probably know very well too, since we’ve been colleagues for years).

One of the main points touched by the article was the long-term ineffectiveness of in-house frameworks. A solution that was developed internally, to bridge a gap in standard implementations, turns later into a drag factor; the short term advantage becomes burden of legacy code and so on.

The old java legacy
One of the reason of “the rise of java frameworks” at the very beginning of this millennium (sounds epical, doesn’t it?) was the low level of abstraction of the java specification itself. JDBC, EJB, J2EE Web were coming out-of-the box without a high level implementation. SUN accompanied the technology with publications such as “Core J2EE Patterns” that used to be a bible in these years. It really sounded like “here is a bunch of small lego pieces hat you can put together to make ... everything! And here (but not in the same place) are the guidelines to make something useful and working properly”.

Unfortunately this is not what many people wanted: people wanted an efficient and solid architecture, easy to set up and reuse. But J2EE offered too many choice-points (how to implement a MVC Model 2? how to deal with JDBC exception? How to make EJB perform? and having the right answer to all he questions was a tough job. So, frameworks were seen as a way to formalize and distill the body of knowledge captured in various patterns book, and to prevent the rest of the team from making awkward choices.

Later on, the implementation of the java platform got better: old EJBs were dropped and many related EJB patterns sunk with them and JSF finally looked like an official standard implementation of a Model 2 MVC framework. It has to be noted that this happened after Spring got momentum, and after the MVC landscape got overcrowded...

Put in this way, there were tons of reasons to build frameworks in those years, because there were holes (or craters) to be filled ...anyhow. Unfortunately some solutions were better than nothing, providing a short term advantage, but rapidly transforming into a legacy nightmare.

If you love somebody, set them free
Some in-house frameworks look definitely naive now, but they looked like (and probably were) a reasonable solution, at the time they were designed (well ...not all of them). Specific design decisions apart, what really makes the difference between a friendly framework and a “traitor” is the cost of getting rid of them. Vendor design frameworks with a very high vendor lock-in potential (it’s part of the game, on the business side), but in-house framework designers often do the same mistake, with no real good reason. Depending on third-party is generally seen as a risk. Depending on yourself is often a higher risk, but seldom considered.

Documentation quality and availability (as Mirco points out) are other key factors, that should make you favor a standard solutions instead of your in-house framework. We used to have a good MVC solution, but switched to Struts as soon as it became a viable option, and so on. Few companies are large enough to afford production of documentation for an in-house framework (one of the reasons why they prefer to sponsor open source projects), so you have to be ready to leap from your solution to the promising open source one, sooner or later.

A framework fills a gap. This means that there is no standard solution for the given problem (otherwise, a framework would probably already be available) and means also that the in-house solution might be non-optimal. This is fine, we’ll probably get more informations about the optimal solution by implementing ours. What we should know in advance, is that we should “design for replacement”, meaning that our framework design solutions should have the primary requirement to be easily discardable. Thus limiting pervasiveness of our solutions.

Often, this is not a technology issue. In-house frameworks have “fathers” that make it difficult to replace them (more or less consciously or willingly) or simply slowing down necessary decisions. Can you be in love with a piece of code? Some do.
   
Which framework now?
Does it still make sense to think frameworks? Well, it largely depends: applications frameworks such as Spring, Hibernate or also Grails offer an off-the-shelf solution to many common architectural problems, leaving architects free to concentrate on application-specific domain decisions. On the other hand they’re all domain-neutral, and a domain specific framework could be of great value for a product company, especially if it is designed to be technology-neutral, and could provide great value in the mid-term.
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