Bob Lee was murdered on April 4 in San Francisco. I met Bob in 2006 when I joined him on the AdWords front end (AWFE) team at Google. He was charismatic, inventive, and kind. With Kevin B. he created Guice, a dependency injector that we could use to make AWFE…
Some of the trickiest bugs I’ve seen happened because a function unexpectedly occurred multiple times on the call stack. Re-entrant ListenersTo illustrate, consider a TextField widget that implements the listener pattern: class TextField { var listeners = mutableListOf<Listener>() var value: String = "" set(value) { val previous = field if (value…
I use lots of factory classes in my code. But not everywhere. I don’t like the ceremony they require to create and use: why not a constructor? Factories don’t solve a business problem directly; they solve an architecture problem. They feel enterprisey and architecture astronauty. /** * For example, a…
Easy code changes are additive: introduce a new database table, network call, or screen. Difficult changes are transformative: split a database table, combine a few network calls, or change a component that’s used on many screens. These changes tend to motivate refactoring: Introduce feature flagsExtract interfacesMove code between modulesAdd…
One aspect of programming that’s more art-than-science is making things efficient. I love finding shortcuts that make a system work better! It’s particularly satisfying to gather insights that we can exploit! I’ll illustrate with an example. Optimal for TodayHttpUrl is a class I wrote that implements URL…
This post expands on a section in my Writing Code That Lasts Forever talk. Here's what it takes to release a new version of OkHttp: Confirm the code is in a releasable state!Name the version (5.0.0-alpha.10 ?, ick)Summarize what’s new in the changelogTag the release…
Let’s make a fictional company that employs workers in two levels: Senior worker: does important work; gets paid $50/hour.Principal worker: trusted with the most important work; gets paid $100/hour.Unfortunately, it’s difficult to differentiate the two levels! If a project completes early it might because…
I presented Nerding Out on Okio at Android Worldwide last month. After sharing the video link and slide deck, Andrew Kelly tweeted asking if I’d share my process. I’m flattered by the question! So here I’ll indulge and share what works for me. The gist of my…