do the ui with double-u
Tuesday 11 April 2006 @ 11:31 am
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It’s framework time. Again. We’ll probably never learn. And on one hand it’s good we do not learn, creativity is partly based on exploring the unlearned. But on the other hand building solutions for already solved problems seems a waste of time. What I’m talking about? New frameworks for solving the UI problem of our world wide web. The list is evergrowing and when looking at the latest additions your homebrew’s name must at least start with a capitol ‘W‘. I’m talking about Waffle’ and Wedge’ Is this the Wicket-effect??

I’m not in the mood, nor in the position, to dive deeply into these two new kids on the block but a quick look through their respective tutorials gave me the impression we’re not dealing with new and fresh approaches. Waffle seems nothing more than an action handling request based view dispatching framework. And Wedge is following the component oriented paradigm and utilizes ANT to generate java code (how about the write-deploy-test cycle??) for binding (indeed, no reflection needed anymore).

But, If you want to give it a try, go ahead! And Feel free to convince me whenever you’re findings do not match my quick look-without-touching way of review. Oh, and for those with too much spare time, I do not care you’re using it to build UI- framework XYZ, but I strongly suggest not to start its name with a trendy double-U :-) .

— By Okke van 't Verlaat   Comments (7)   PermaLink
Productivity versus design
Wednesday 5 April 2006 @ 3:06 pm
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In his excellent written article The state of design Steven Devijver makes some intriguing comments on common design principles. While advertising the principle of simplicity, he focuses on the effect EJB technology had on current practices. Major target of critique is the inherited (as in taken from the olf J2EE world) use of data transfer objects while everyone seems to have forgotten the idea of rich domain models. You can agree with him or not (as one can follow on the discussion full of lengthy replies at javalobby.org), but one point he makes seems evident: when dealing with an object oriented world (language, platform) why restrict yourselves to behaviourless classes? It’s a bit of missed opportunity he forgot to mention how complex OO can make life and how delighting DTO’s can be. I do agree with Steven we not always get the best out of the OO instruments we are using but sometimes I also wonder for whatever reason we decided it must be OO (not even mentioning the additional layer on top dealing with cross cutting concerns). Not everybody is a PhD in applied computer science! At the end, a design will be settled by the fact it resulted in a piece of software that works and that was build within budget.

The last months I’ve been busy exploring productivity boosts around web application development. And during this quest I discovered there are only two major streams to follow: You either simplify everything you can and make life as easy as possible especially by underdesigning your app, or you don’t care about complexity that comes with ‘well designed’ OO and rely on the tools you use. No middle of the road! Setting up a rich domain model without the tools to maintain it? Forget it! But on the other hand you can also forget to build an utterly complex application without any design. It seems to be either the complete low- or the complete high-end of bandwith. So you either end up in a Ruby on Rails alike world with simple models (indeed, DTO’s without behaviour), simple controllers and a couple of useful helpers, or you find yourself behind a ‘do everything a normal programmer does not want to do by himself‘ kind of RAD environment. And it’s exactly this perspective you have to use when looking at ‘the state of design’: It’s all about productivity.

So, that said it’s time to drop in the bit over-acted and bold statement Java is not a very productive language. Neither is C++, neiter is C#, neither is any 3GL (not going to argue a language producing byte code that get interpretered by a virtual machine is not pure 3GL!). When you’re planning to write a data driven web application by hand using java, no matter which (set of) frameworks you’re planning to lay as foundation, the language you’ve choosen will become your biggest enemy. You might have the most elegant framework you could find (yep, of course it is Spring), you can have the most elegant design (including those lovely rich domain models) but the chance you got beaten by a bunch of scriptkiddies who just met the Rails environment is quite high. Unless you got tooling! Heavy tooling! And once you’ve got your ironwork, I bet you won’t care about design at all. That is up to the tools and embedded (meta) frameworks you bring with you. So, if you ask me what the state of design is, I would say it has been forgotten. Design has left the building. For the sake of productivity.

— By Okke van 't Verlaat   Comments (0)   PermaLink
It’s just common(s) sense
Monday 3 April 2006 @ 9:59 am
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Most java projects use a bunch of common classes for various things.
Because this functionality is so common, we tend to copy these common classes from one of our earlier projects.
Instead of just copying some ‘legacy’ snippets from previous projects, it might be a more sensibly thing to use the (Apache) Jakarta Commons libraries instead.
One of the jakarta commons should be mandatory for each Java project: Commons Lang

The commons lang contains all kind of utility classes that will make you think why it is not part of the standard Java lang(uage).

One of the most handy features of the Commons Lang are the Builder classes to easily create toString, equals and hashCode implementations for a class. All these builder classes are smart enough to detail with null and array arguments, so you don’t have to.

Another handy class is the StringUtils class that contains a whole bunch of string functionality like isEmpy / isBlank, trimming, replacing, chomp / chop etc.

When coding I like to aggressively enforce my constructor / method pre-conditions by throwing and IllegalArgumentException when any argument value is not according to a pre-condition. The Validation class will help you with that. It contains utility methods to easily check if the supplied argument isTrue, notEmpty and notNull. Furthermore for a collection / array you can easily validate if there are no null element and that all elements are of a certain type.

There last class I would like to mention is the Enum / ValuedEnum base class.
By extending from this class you can easily create a enum class in Java 1.4 (in Java 5 you should use the new enum language functionality).

I would advise any Java programmer to have a (short) look at the Javadocs of Commons Lang, because besides the features I described above there are a lot more gems to be discovered.

— By Emil van Galen   Comments (0)   PermaLink

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