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#enumsmatter

Colt McAnlis has been arguing that Android developers avoid enums because they have a non-negligible runtime cost compared to int constants. In his talk he measures it, and suggests that pervasive use of enums can harm your Android app.

“And the worst part is that you don't really know that enums are causing a problem until they're already infecting your codebase. And by that point trying to fix it is really a horrible process.”

The implied alternative here is a codebase that uses a single type – int – instead of a variety of different enum types. He wants us to go from this:

  public PaymentState cancel(String id, CancellationReason reason);

to this:

  public int cancel(String id, int reason);

That codebase is harder to maintain and I wouldn’t want to work on it! The reason the entire Internet was disgusted by Colt’s advice is that it takes one of the few tools we have to help us to write readable code (types!) and discourages its use.

#enumsmatter