f3yourmind

It was really good to be part of a very topical subject at the JCSE Architecture Forum last night.  While these discussion are so valuable, the things that surface can only be glossed over, largely because of time constraints.  I end up feeling a very satisfied and energised but a part of me feels a bit hollow.

So here are some of the things that surfaced at the Forum, and my narrow, unworldly opinion on each (i.e. I’m just trying to fill that hollow feeling).

When we talk about architecture, we need to define what we mean by architecture?

In my talk it was a very simple view of architecture which, thinking back, I should have disclosed very early.  I am now applying from Kent Beck who talks about mutually beneficial relationships.   So I think of architecture as the mutually beneficial relationship between two or more things.  So what is a thing?  It could be  lines code in a method, methods in a class, classes in namespace, namespaces in code base, binaries in an application server, application servers in a cluster, … see where I am going?  Architecture is about creating beneficial relationships, and the 5 things I discussed are based on this view.  If you don’t know anything about the things, then you cannot create beneficial relationships.  From an agile perspective, the beneficial relationship that you create should only be beneficial based on your knowledge right now.  Tomorrow your knowledge changes, so the relationship may not be as beneficial as yesterday.  Time to change.

Building infrastructural architecture independently of functional requirements…

I am not convinced of the benefit of this approach.  In my limited experience, every business need defines the constraints or needs of the infrastructural architecture.  I find it hard to find the point of departure, yet there is a school of thought that suggests that function is orthogonal to the architecture.  Perhaps I just don’t understand this.  However from an agile perspective, I want to release early and there are many constraints on infrastructure from the business (for example, administrative processes like procurement of hardware).  I like to understand what these are early on, reach agreement on what we can release at the earliest and design accordingly.  Perhaps the first release is on lightweight infrastructure and that means we “limit” scalability.  So, I don’t design for beyond what I know is real.

Model Driven Architecture …

My view is more philosophical and abstract.  What is a model?  For me, a model is something intangible.  It is a way we understand something.  But we represent our models in many ways.  Through words in written or spoken conversation, in unstructured pictures, in structured notation like UML, even code is a representation of a model.

What do we mean by driven? I view it as a something that takes an input that produces an output.  In this case, we take an input, the model, and produce an output, an architecture.  So, I take an understanding of problem and use that to derive an architecture.  So, that’s nothing new here.  However, I don’t like to confuse driving out an architecture from a representation of the model.  That’s different.  Now we are going beyond thought processes  into mechanical processes.  Then the challenge is about how to apply the feedback to the representation of the model – and that is what will make you agile.  Too much for my small brain.

Plumbing …

Yup, we do too much hand crafted plumbing!  It’s something that we have been working on for a long, long time.  I think convention over configuration, dependency inversion, meta-programming are all attempts at addressing this problem.  Some early success that I have experienced is on taking a polyglot approach. I am not talking about mixing general purpose languages on one runtime only.  I am also including domain specific languages. I’ve had some early success where using DSL to describe functional intentions and then generating a large portion of the plumbing.  Where I’ve suffered is when I mix concepts from different domains.  There is the domain of plumbing and the domain of the business.  Whenever I’ve mixed the two, it pains later rather than sooner.  Right now, the only way I’ve had some success is with aspect orientation and meta-programming.

@StatelessSessionBean …

Chris Naidoo is right.  That thing called J2EE and subsequent versions is just horribly broken.  It’s broken encapsulation and a whole lot more.  The fact that we now must use an annotation and not implement an interface is immaterial.  Both result in the same pain – mixed concepts (see plumbing above).  Annotations should be specific to the business such as @RecalculateCostsOnRerouteOfCargo can be used as an interception point for injecting a rule on a class or method.

I would go even further and say that the POJO JavaBean specification is also broken.  Why on earth must I have a no-argument constructor and accessors and mutators.

Last thoughts …

I may have missed some of the other discussions but these are the ones that I woke up with this morning. In general, my observation is that we need to be very concrete very early if we want to be agile, even in architecture.

I have no idea what I’ve gotten myself into now, but I’ve agreed to help out the Empirical Evaluation of Software Composition Techniques workshop will be held as part of the next Aspect Oriented Software Development conference.  I doubt I will attend ESCOT or AOSD but it will be good to collaborate once more with some very enlightening people that I met at OOPSLA last year.

I guess I’ve got quite a lot of reading coming up and it will be fun to read what is coming out of the research channels and cast my own weird industrial perspective on things

In a couple of weeks I will be at the OOPSLA conference in Orlando, USA.  I am absolute OOPSLA nOOb but am already excited about it.  I’ve heard lots of nice things from the OOPSLA “veterans” at factor10 and now I can’t really wait to get there.

I will be giving a tutorial on using AOP to solve some domain problems, not just removing the infrastructural noise from your domain models.  Also, I’ve been invited to be part of a panel on my best-loved-hated subject … modularity.  I will also take part in the Cloud Computing Design workshop.

There’s also an amazing line up for the other tutorials and OOPSLA still has a “Pay for 3 and attend 4″ promotion going on.  Take advantage of it.  If you already signed up for 3, then just sign up for the 4th.  If you’ve signed up for 2, then pay for the third and register for the 4th too.

So much happening in just a short week.  But, it will be lot’s of fun and worth the 24 hour travel time from Cape Town.

Trust has popped up in so many of my conversations recently.  It came up at home, at a new school that Lia will be starting next term, in the DDD course that I gave earlier in the month, in Peter Hundermark’s scrum master certification course.  And I got a one line email that said this.

The entire world lives on trust. Every aspect in life moves with trust.

The more I think about situations in life that will prove this statement false, the more it seems to hold true.  Even in design it holds true.  Your most fundamental architectural decisions are based on trust and the implementations of that architecture work because of trust.

It’s true for code too.  If you don’t trust the code on which you build or depend, then you might as well write everything yourself, and give up your place on your team.

I was thinking about the AOP with DDD tutorial that I will be giving at OOPSLA this year, and this trust thing came up.  Here again, aspects and the classes into which they get woven, need a trust relationship.  It may seem like a stretch to make that statement, but I think it holds true again.

So, how do you gain trust?  I am not sure, but I think you have give up something first.  Maybe you need to show your vulnerability first, then it becomes easier to let someone into your space.  Then, perhaps, they will let you in to their space too.  When ego walls are erected, then trust finds it hard to grow.  By ego, I don’t mean arrogance, I mean awareness of your self that you hide from others for fear.  Perhaps, it is only when you show your true interface, that the other will worry less about hidden agendas.

In code, trust lies in interfaces and types, not in implementations.  It’s really about trusting the implementation that makes types worthy.  When you trust the type and send it a message and it behaves as expected, then you trust it.  If you request something of an abstract type and the message was received by an instance of a subclass, then you expect the subclass to behave like the abstract type.  You don’t hope that it does behave consistently, you trust that it does!

Trust is tied in with ubuntu too.  You can’t be part of a community nor allow yourself to be defined and shaped by the people around you, if you can’t trust them.  I think ubuntu coding needs trust as one of it’s values.  It’s already a value in XP, and Scrum, and families.  It needs to be in teams, and organisations, and communities and nations too.

It’s already halfway through the year, so let’s see what events are is in store for the rest of the year.

June: Next week is SPIN week.  Join us after the June 16 public holiday.  Same time, same place.  Last month we had 40 people attend and we just about ran out of chairs.  Lots of new faces.  Please come along.  The talks are normally good and the conversations are great.

July: Really need to get my act together and get to the next SA Developer’s talk.  Hilton Giesenow tells me it’s a great local event.  And On July 27, Lia turns 5!  Simply amazing!

August: Hmmm, seems quiet?  I think I’m going to submit a tutorial proposal for the ICSE conference happening in Cape Town in May 2010.

September: Looking forward to the Scrum User Group’s conference in early September.  I may be giving a talk on the techie track.  I think it’s going to be a great event.  Carlo and Peter tell me so.  But on September 3, Fiona turns … older

October: My tutorial on using DDD and AOP to create clean, rich domain models has been accepted by OOPSLA.  So, October is OOPSLA time for me.

November: I will miss Oredev.  The competition to get in was so much tougher.  That just means it’s going to be better than last year.  If you’re a S.African developer, you should make a plan to get there.  It’s a great event that is very high on value for money.  But my November highlight is Khaleel turning 9 on the 22nd!  Boy, how did that happen so fast?

December: Crazy season again.  I really hope it’s a quiet, relaxing one this year.