Don’t make me think. That’s how I feel about your code.

Or as Martin Fowler puts it:

“Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” -Martin Fowler, Refactoring: Improving the Design of Existing Code

You’ve reached a whole new level of mastery when you write for simplicity, elegance, and maintainability. This is done on purpose, and it’s hard to get right. Deadlines, schedules, pressure, and stress all encourage us to cut corners and adopt a “Git ‘er done!” mentality. But Abandonment of planning under pressure is one of software’s classic mistakes. It’s a cardinal sin.

How do you write simple and maintainable code? I’ve got a 3-step program for you:

Step 1: Admit that simple isn’t easy

Designing simple software is hard. It has to be done on purpose. You can’t accidentally find yourself with well-written code and an elegant solution, it has to be written that way on purpose.

This admission is a bedrock principle required for designing great software and products. If you can’t admit that simple is Hard Workâ„¢, you haven’t hit rock bottom yet by having to maintain code that would make readers of The Daily WTF blush.

Step 2: Read “Don’t Make Me Think”

Steve Krug’s excellent book “Don’t Make Me Think” is about website usability, yet it changed how I look at my code.

Why? Because Steve applied the same principles in his book to his book! And if it works in those two mediums, I thought it just might work for me, too, in my medium (code).

“Don’t Make Me Think” is very easily absorbed because he’s feeding you information in a readily accessible way. He wrote it simply on purpose, and I’m certain it took many more hours to edit than it did to write. Simple is hard.

Step 3: Practice simple everyday

There are innumerable decisions you make everyday that affect your project for better or worse. You need to recognize these as the opportunities they are. Here are a few things you can do every day:

  • Code in plain English. Use an active voice (just like writing). What do you think this method does?
  • dao.findCustomerBy(order);

    Or what about this if statement?

    if(admin.hasPermission(Permissions.VIEWFILE)){
       // allow...
    }

    or better yet…

    if(admin.hasViewFilePermission()){
       // allow...
    }

    The pretty method on the Admin class looks like this:

    public boolean hasViewFilePermission(){
       return hasPermission(Permissions.VIEWFILE);
    }

  • Make Stuff Obvious. Quick, what does this line of code do?
  • Date dt = march(28, 1973);

    When I’m reading through unit tests, I’d much rather see the above statement to create a date than the equivalent Java:

    Calendar cal = Calendar.getInstance();
    cal.set(Calendar.MONTH, Calendar.MARCH);
    cal.set(Calendar.DATE, 28);
    cal.set(Calendar.YEAR, 1973);
    Date dt = cal.getTime();

    You can find those convenient date methods here: dates.java (it’s Free software). Use Java 5’s static imports to make the short date seen above.

  • Be Merciless. Be your own worst critic when reviewing your code. Always strive to improve what you’ve written. Just as great essays and novels (and books like “Don’t Make Me Think”) require several rounds of editing, so too does your code.
  • Never nest ternary statements. ’nuff said.
  • Write comments, but be brief and explain why your code does what it does, not how it does it. We already know how it does it, we’re looking at the code.
  • That’s it. Three steps to better code. Putting it into practice won’t be easy, but if you want to be a master of your craft you’ll embrace the challenge and write things simply on purpose. The people who follow you and maintain your code will appreciate it.