My name is Martin Fowler: I’m an author, speaker, and loud-mouth on the design of enterprise software. This site is dedicated to improving the profession of software development, with a focus on skills and techniques that will last a developer for most of their career. I’m the editor of the site and the most prolific writer. It was originally just my personal site, but over the last few years many colleagues have written excellent material that I’ve been happy to host here. I work for ThoughtWorks, a really rather good software delivery and consulting company. To find your way around this site, go to the intro guide.


News and Updates

My atom feed (RSS) announces any updates to this site, as well as various news about my activities and other things I think you may be interested in. I also make regular announcements via my twitter feed, which I copy to my facebook page.


Show the User Journeys

Thu 23 Mar 2017 15:55 EDT

Next activity for Paulo's Lean Inception is to explore the journeys that users follow to reach their goals. The team plots out the steps of each journey on a large chart ready for the next activity.

more…


Technical and Business Review

Wed 22 Mar 2017 07:56 EDT

Up early on Wednesday, so ready for the Technical and Business Review activity of Paulo's Lean Inception. During the morning the team reviews the features and assess their value, effort, and level of uncertainty.

more…


Discover the Features

Tue 21 Mar 2017 15:38 EDT

It's Tuesday afternoon, and for once the day of publication matches the day of the week in the Paulo's Lean Inception timetable. For this afternoon, the activity is Discover the Features. The team uses a prioritized grid of personas and goals to consider what features should be in the product.

more…


Describe the Personas

Mon 20 Mar 2017 09:58 EDT

To build a product, we need to understand who our users are and what they want to achieve. So on the Tuesday morning of a Lean Inception, Paulo gives us an activity to describe the personas of our users.

more…


photostream 106

Fri 17 Mar 2017 21:34 EDT

Roy's Peak, Wanaka, New Zealand


What the Product is (and isn't)

Thu 16 Mar 2017 09:05 EDT

Paulo continues his Lean Inception discussion by moving onto an activity that explores the key characteristics of the product. Participants explicitly list both what the product does and what it does not do.

more…


The Lean Inception

Wed 15 Mar 2017 09:37 EDT

Agile projects don't start with a detailed plan, but let the direction of a project emerge as we learn more. But there is value in doing some upfront work to determine the vision of a new development. At ThoughtWorks, we carry out inception workshops to help do this.

Paulo Caroli has developed a style of one week inceptions, that are particularly suited for sketching out the characteristics of a Minimum Viable Product (MVP). In this evolving article, he'll outline this one week workshop and what goes into it. He starts with Monday morning's activity "Write the Product Vision". We'll be publishing further activities over the next few weeks.

more…


Bliki: SelfEncapsulation

Thu 09 Mar 2017 08:17 EST

Data encapsulation is a central tenet in object-oriented style. This says that the fields of an object should not be exposed publicly, instead all access from outside the object should be via accessor methods (getters and setters). There are languages that allow publicly accessible fields, but we usually caution programmers not to do this. Self-encapsulation goes a step further, indicating that all internal access to a data field should also go through accessor methods as well. Only the accessor methods should touch the data value itself. If the data field isn't exposed to the outside, this will mean adding additional private accessors.

more ...



Refactoring

Refactoring has become a core skill for software developers, it is the foundation behind evolutionary architecture and modern agile software development. I wrote the original book on refactoring in 2000, and it continues to be an interest of mine.

I’ve recently posted several essays on refactoring here:

  • JavaScript offers many targets for refactoring, so Refactoring a JavaScript Video Store takes the original video store example from the book and explores it in JavaScript. It outlines four directions you can take the refactoring: a nested function with a dispatcher, using classes, and transformation using an intermediate data structure.
  • While most of our logic is written directly in an imperative language, it is sometimes very useful to represent such logic in a data structure. Refactoring to an Adaptive Model describes this refactoring, which produces an adaptive model interpreted by generic code.
  • As a program grows in size it’s important to split it into modules, so that you don’t need to understand all of it to make a small modification. In Refactoring Module Dependencies I modularize a small example using layering and introducing Service Locator and Dependency Injection. I illustrate these using both Java and JavaScript so you can see how this modularization looks in different languages.
  • When I write code that deals with external services, I find it valuable to separate that access code into separate objects. Refactoring code that accesses external services shows how I would refactor some congealed code into a common pattern for this.
  • Modern languages give us the opportunity go beyond the loop as a way of handling repetitive behavior. Refactoring with Loops and Collection Pipelines provides a series of small examples of refactoring loops into my preferred approach.
  • Refactoring Code to Load a Document looks at how manipulating large JSON documents can often be made easier by encapsulating a combination of loading strategies.

TW logo

I discovered ThoughtWorks in 2000: then a small American company whose philosphy of software development was remarkably similar to my own. Now we’ve grown to around 4000 people world-wide, but kept the values that make us special. My colleagues have built critical systems for many clients in that time, and I’ve learned many lessons from them. While doing this, we found we often didn’t have the tools we needed, so we started to build them. This led to open-source tools such as CruiseControl, Selenium, Frank, and Moco as well as commercial products.

I have many opportunities, but I’ve stayed at ThoughtWorks because of the quality of my colleagues, who include both well-known speakers and those who may not be famous names but do an excellent job of software delivery (and feed me the information to write about). We are inspired by working with each other and our unusual three-pillar philosophy that raises professional excellence and social justice to the same level as financial performance.

And we are always looking for more great people to join our curious company. Maybe I’ll see you in one of our offices some day.


Continuous Integration and Delivery

For a long time I’ve been a champion of Continuous Integration which reduces integration risk by integrating early and often, an application of the principle of Frequency Reduces Difficulty. We’ve found CI to be a core technique at ThoughtWorks and use it almost all the time. At the heart of this is a style of development that minimizes long feature branches with techniques like Branch By Abstraction and Feature Toggles.

While this is useful, there was still risk present from software that works in the development environment to getting it to work in production. As a result we developed Deployment Pipelines to reduce this risk, moving closer to our aim of Continuous Delivery: building software in such a way that we confidently deploy the latest builds into production whenever there is a business need. We find this improves feedback, reduces risk, and increases the visibility of project progress.

For more information: take a look at my guide page on Continuous Delivery.

photo: Manuel Gomez Dardenne



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