CodeSOD: Swing and You're Out

George G was hired to do some UI work for a company which sold a suite of networking hardware. As networking hardware needs to be highly configurable, George was hired on to do "some minor tweaks" to the UI. "It's just some sizing issues, fonts, the like. I'm sure you'll do something to the stylesheets or whatever," said the boss.

The boss didn't know what they were talking about. The UI for some of the products was a web based config tool. That was their consumer-grade products. Their professional grade products used the same Java program which was originally released 15 years earlier. There were no stylesheets. Instead, there was an ancient and wobbling pile of Java Swing UI code, maintained by a "master" who had Strong Opinionsa about how that code should look.

For example, dispatching a call to a method is indirection. Indirection is confusing. So inline those calls, especially if there's a conditional involved: inline all the "ifs". Factory methods and other tools for constructing complex objects are confusing, so always inline your calls to constructors, and always pass as many parameters as you can, except for the times where you don't do that, because why would we be consistent about anything?

All of the developers on the project had to attend to the master's wishes during code reviews, where the master gleefully unrefactored code "to make it more clear."

Also, keep in mind that this UI started back in an era where "800x600" was a viable screen resolution, and in fact, that's the resolution it was designed against. On a modern monitor, it's painfully tiny, stuffed with tabs and icons and other UI widgets. Over the years, the UI code has been tweaked to handle edge cases: one customer had the UI zoom turned on, so now there were piles of conditionals to check if the UI needed to be re-laid out. Somebody got a HiDPI display, so again, a bunch of checks and custom code paths, all piled together.

Speaking of layout, Swing was a prime case of Java taking object orientation to the extreme, so in addition to passing in widgets you want displayed, you also can supply a layout object which decides how to fill the frame. There was a whole library of them, but if you wanted a flexible layout that also handled screen scaling well, you had to use the most complicated one: Grid Bag. The Grid Bag, as the name implies, is a grid, but where the grid cells can be arbitrary sizes. You control this by adding constraints to the flow. It's peak Java overcomplification, so even simple UIs tend to get convoluted, and with the "inline all the things" logic, you end up with code like this:

if( os.getSystemFontSize( NORMAL ) == 14 )text = new JText("5", new GridBagConstraints(3, 1, 3,3, 1.0, 0.5, GridBagConstraints.PAGE_END, 1.5, Insets(10,5,10,5, 5, 5 ) );else text = new JText("5", new GridBagConstraints(3, 1, 3,3, 0.99, 0.4, GridBagConstraints.PAGE_END, 1.5, Insets(4,2,4,5, 5, 5 ) );

This particular code checks to see if the user has their font set to 14pt. If they do, we'll set a constraint one way. If it's any other value, we'll set the constraint a different way. What is the expected result of that constraint? Why all this just to display the number 5? There are a lot of numbers other than 14, and they're all going to impact the layout of the screen.

George made it two months, and then quit. This happened just a week after another developer had quit. Another quit a week later. No one in the management chain could understand why they were losing developers so quickly, with only the master remaining behind.

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