Tag Archives: agile

Modeling out Loud Deep Dive

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For those of you that attended the Modeling out Loud deep dive at the S.Africa Scrum Gathering today, here are some things that I discussed.  It’s in no particular order, and it only makes sense if you attended the session.

  • BDD Stories that are authored outside the team contributes to a hand-off which influences design decisions.
  • Because we understand something does not mean that we know how to design it.
  • Be aware of when you are analysing and when you are designing.
  • Be concrete and abstract late.
  • Use the scenarios to close the loop with product owners, stake holders, etc.
  • Developers should write BDD stories and scenarios.
  • We are less ignorant at the end of the sprint than at the beginning.
  • Use code to close the feedback loop for your story.
  • A story and it’s scenarios can be a representation of your model, just like a picture, UML, test code, production code.
  • Seek out the behavior and express intentions.
  • Use the value statement to explore alternative needs.
  • Product owners should not write BDD stories
  • Recycle stories if there are scenarios that you cannot commit to.
  • Keep out the technical jargon.  The moment you get technical, then the story shifts to an implementation.
  • Evolve and accept that it is ok to change … your story, your scenario, code, anything.
  • Login is not a story

There was a lot more which we all discussed, so feel free to add what you got out of it as a comment for others to grab.

The slide deck which contained the code example is available at http://bit.ly/bhNkvQ.

And lastly, thanks for joining in.  I sincerely appreciate you making the time.

Remember that writing stories is a really difficult thing to learn, because is design is hard.  Persevere.

Resurfacing Diversity Challenges

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I got a tweet from Clive Seebregts which pointed me to an InfoQ article that made reference to an old Hanselminutes podcast that I did.  It’s nice to see that diversity is not being left in the wilderness and that other people are thinking about it again.  It seems like some people are trying to promote diversity and others are trying to manage the challenges of diversity.  Hmmm, somewhere there is point of brutal contact, but it will be for the good.
BTW, digging around on material diversity in agile teams I came across this video.  I didn’t know it existed at all.  Suddenly, the references to the FIFA 2010 World Cup seem sooooo dated.

Reflections on the JCSE Agile and Architecture Talk

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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.