Variable and method naming conventions for boolean verbs in Java? [duplicate]

Question

I know that many suggest this convention:

boolean deleted;
boolean isDeleted();

But what do you do when you want to name a boolean to indicate that a user can leave?

boolean userCanLeave
boolean isUserCanLeave()

boolean canUserLeave
boolean isCanUserLeave()

boolean userLeave
boolean isUserLeave()

boolean userLeave
boolean canUserLeave()

I'm not sure if there is any standard for this or do you just take the one you think is most readable? It is the variable to getter method name mapping that is interesting here.

Answer 1

You should use a better variable name like userAllowedToLeave.

And, then use the getter method as isUserAllowedToLeave().

This at least uses the "is" getter, and sounds grammatically correct too.

Answer 2

Using booleans like this is almost always a bad and confusing idea. If you want to make your code understandable and easily maintainable you should use an enum to represent state, maybe with strong transition rules (an FSM).

Assuming that your 'leave' concept is based on whether a user has completed a task or set of tasks, then you might have

public enum UserState { inProgress, complete }

You could then implement a method leave on your user class like this:

public void leave() { if (state == UserState.complete) ... }

where state is a private instance of the enum defined above. You can then reframe the question isLeaveable to getState, if such a thing is needed. Of course, you'd also need a complete() method which would change the state appropriately and which would be called when the user has completed their tasks.