Just the thought of ‘refactoring’ can be daunting to a programmer.
Martin Fowler defines ‘refactoring’ as:
Refactoring is a disciplined technique for restructuring an existing body of code, altering its internal structure without changing its external behavior. Its heart is a series of small behavior preserving transformations. Each transformation (called a ‘refactoring’) does little, but a sequence of transformations can produce a significant restructuring. Since each refactoring is small, it’s less likely to go wrong. The system is also kept fully working after each small refactoring, reducing the chances that a system can get seriously broken during the restructuring.
When I first started to look at our library of Legacy Code my first thought was to just scrap the library and start over. Now try to sell that idea to the stake holders. Not going to happen is it. So that’s where refactoring come’s in. But there are a few obstacles we have to over come in this process.
- Sell the process to the product owner/business:
J.B Rainsburger used an analogy that helps us with this obstacle. The use of credit cards. Each time we purchase an item with a credit card, we are purchasing that item with something we don’t have which is money. Now let’s take this and apply it to programming against that library of legacy code. Each time we do we are developing on credit and spending something we don’t have which is time.
- Single Methods with large amounts of code:
First let me refer you to an excellent book by Michael Feathers titled Working Effectively with Legacy Code
. In this book Michael suggests that we take that method and create a class with only that code. With this class we can now start writing unit tests for the code and begin refactoring. Now in our legacy code where we just pulled the large method from create a call to the method in our new class.
- Duplicate Code:
“When N things need to change and N>1, Shalloway will find at most N-1 of these things.” Basically what Alan Shalloway is saying here is that if you have more than 1 duplication of code chances are high you won’t find all instances of that duplication. This is where design patterns come in and the phrase “refactor to patterns”.
- Where do I start?:
The hardest obstacle to overcome is where to start. Practice
- Start off by finding a section of code that you feel may could use some refactoring.
- Work on refactoring it for 30min.
- Throw that code away.
- Take a break
- Repeat.
“Throw away my code!!!” you might be saying to yourself right now. Yes, Throw it away. What this does for you is reminds you that you are just practicing and 2nd it separates you from your code.
- TDD and Refactoring?: Yes its possible. As you go through your refactoring you’ll see that you are refactoring to patterns, while you are doing this, ask yourself “how would I want to test this code?” Retrain your way of thinking in how you approach code and you’ll soon find yourself refactoring through TDD and Design Patterns.
So there you have a few tips on how to overcome a few obstacles when you start to look at refactoring your legacy code for the first time.
David Yancey
Why does it seem that the .NET Community isn’t very active in the Agile community? I know that there are Agile practitioners in various .NET shops however, it seems that the overall representation is very minimal. Is it because of a lack of understanding of the Agile methodologies? Or is there a lack of support and resources for the .NET community when it comes to Agile practices?
I just got back from the Agile Development Practices by SQE and I felt like I was in the minority there. As I went from sessions on TDD to Design Patterns to Refactoring each time it was asked what platform each of the developers were on I was one of 2 or 3 that mentioned .NET. The majority was Java with a small representation of Ruby developers, which on one hand I’m glad because I got a great exposure to Java and Ruby, however on the other hand it raises the questions as to why.
So what is Agile?
Agile Manifesto:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
That is, while there is value in the items on
the right, we value the items on the left more.
Looking at the principles behind the manifesto we see more of what really is the driving force of the Agile movement and begin to understand why it is important to all developers to grasp this concept.
- Our highest priority is to satisfy the customer
through early and continuous delivery
of valuable software.
- Welcome changing requirements, even late in
development. Agile processes harness change for
the customer’s competitive advantage.
- Deliver working software frequently, from a
couple of weeks to a couple of months, with a
preference to the shorter timescale.
- Business people and developers must work
together daily throughout the project.
- Build projects around motivated individuals.
Give them the environment and support they need,
and trust them to get the job done.
- The most efficient and effective method of
conveying information to and within a development
team is face-to-face conversation.
- Working software is the primary measure of progress.
- Agile processes promote sustainable development.
The sponsors, developers, and users should be able
to maintain a constant pace indefinitely.
- Continuous attention to technical excellence
and good design enhances agility.
- Simplicity–the art of maximizing the amount
of work not done–is essential.
- The best architectures, requirements, and designs
emerge from self-organizing teams.
- At regular intervals, the team reflects on how
to become more effective, then tunes and adjusts
its behavior accordingly.
The early continuous delivery of quality working software through continuous attention to simplicity, technical excellence, good design where the business and developers form a team to work together frequently reflecting how to become more effective through self organization.
This is just the beginning however, Agile goes beyond just what is stated in the manifesto. There are methodologies for all aspects of the business, from the executives with LEAN, to the team with SCRUM down to the individual developers with XP (Extreme Programming). Some of the concepts with in XP will be quite familiar to the .NET community, such as Test Driven Development (TDD) and Pair Programming.
I want to encourage all developers to really look into what Agile has to offer and then take it to your business and challenge them to implement Agile as your new methodology. If you are already doing Agile then start speaking up about it. Make your presence known and help evangelize Agile in the .NET community.
David Yancey
