Personal opinion on software development in general, development methodologies, tools and best practices in particular

Archive for February, 2010

Standards: Pros and cons


It’s widely accepted that it’s a good idea to use standards in software applications. But is this really true?

Let’s take JPA (1.0) vs Hibernate as an example. A lot of people use Hibernate as JPA implementation in their project. The idea is that one can easily switch to another ORM framework that implements JPA.
That sounds as a very good pro but what is the chance that within that specific project another implementation than Hibernate will be used? Why would you want to change?

Standards are made to introduce a general way of working. If you know JPA you don’t have to learn specific implementations like Hibernate, iBATIS or TopLink . That’s true. But what if the standard doesn’t support everything that a specific implementation can do? Will you still use the standard even if you lose some features? In my opinion the answer to that question is definitely ‘no’!

Did you ever try to make use of delete-orphan with JPA? You just can’t do that for the simple reason that it’s not supported by JPA. Solution: use the Hibernate implementation instead.

Another example: Criteria API. You can use Hibernate’s Criteria API for retrieving entities from the DB. It’s not included in JPA. Same for Hibernate Validator. It’s not (yet) included in JPA. So we still use Hibernate specific code.

I know it’s included in JPA 2 but to be honest, how long will it take till a lot of projects will use JPA 2? It can take some time until a new version of some framework will be adopted by a lot of people. The point is that standards seem like a good idea but most of the time not enough features are available at the time the first stable version is released. They’re immature at the moment a lot of people start using them. Which means that the introduction of a lot of standards comes too late.

In my opinion standards can be useful in a long-term project subject to a lot of change like a framework or something similar. But in most of the fixed price software projects an immature standard can be contraproductive instead of generating a lot of added value.

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Focus on quality


Why do a lot of people say that testing is a waste of time? Because it takes time to write software tests? Hmm looks kinda strange don’t you think?

Software analysis, design, programming, bugfixing,… are all time consuming activities that are part of the application development process and it’s accepted that those activities take a lot of time so no one ever thinks about skipping them. So why would people skip testing? Because they like bugs? Because they hate visibility? Because they like bad quality?
Oh now I remember, because tests are obsolete and cost time and money. And we’re getting out of time or out of budget so we skip tests. Big mistake!

Tests are also part of the development process! Why? For many reasons!

  • Tests create visibility and a safety net. By writing tests you can pinpoint bugs as soon as possible. And you can fix them as soon as possible.
  • Tests reduce the amount of bugs in new and existing features. Because we see bugs by writing tests, we can fix them and reduce the amount of bugs.
  • Tests allow refactoring. Because there’s a safety net, you can refactor without fear. Tests will be broken if the refactoring failed.
  • Tests reduce the cost of change. Because you see and fix bugs as soon as possible, you don’t introduce extremely long bugfixing phases. The longer the bugfixing phase, the more money that will be spent to fix the bugs. The graph below explains everything.

Most bugs are introduced in the coding phase and this phase is the cheapest one to repair bugs in. So we can conlude that quality is what we should focus on. You can do this by writing enough tests but there are other ways to do it:

  • Don’t overdesign. Of course you should think about the design first but don’t program with the idea that maybe this feature could be useful. A  software application is not meant to exist of several selfmade subframeworks that contain unused features. Thinking about those features and writing them is a waste of time in fact.
  • Design as late as possible. If you write some code, do not think about reuseablity at that moment. Extract the code at the moment you wrote the same code twice.
  • Refactor as much as possible. When time’s ready, refactor code to keep it clear, readable and maintainable. Code duplication is a bad practice.
  • Use tools to track possible bugs. Findbugs and PMD are very useful.
  • Make use of continuous integration. CI will tell you that something will be broken, so if CI is green, you don’t have to bother about it.
  • Do code reviews of each others code. Every developer has an other point of view and will detect bugs and bad coding practices that you didn’t notice because it’s your code.

So if you don’t like to focus on quality but on costs, remember that by focusing on costs, quality won’t improve. No, quality will even be worse, meaning that it will even be more expensive to guarantuee a product without major bugs and thus costs will raise by fixing a lot of bugs at the end of development! If you focus on quality from the beginning, costs will be reduced and quality will even get better.

An easy formula can illustrate this:

So please please if you’re thinking about dropping tests to save money, think again! Focusing on quality is the only way to reduce costs.

References:

http://onjava.com/pub/a/onjava/2003/04/02/javaxpckbk.html

http://blogs.windriver.com/graham/2010/01/service-and-repair-is-not-the-only-option.html

http://en.wikipedia.org/wiki/W._Edwards_Deming