Not super comfortable with sealed classes. I'm trying to model an action type that can model things ...

# getting-started

[Colton Idle]

Not super comfortable with sealed classes. I'm trying to model an action type that can model things like a phone button click, or a url click, or unhandled (unknown).

How does this look?

sealed class GenericActionType {
    class Dialer(phoneUri: String) : GenericActionType()
    class Browser(url: String) : GenericActionType()
    object Unknown : GenericActionType()
}

[Joffrey]

The structure looks good to me, although I would probably use data class for the ones with data, it's often useful for printing/copying/equaling etc.

Regarding naming, maybe avoid "generic" and "type" in the name:

• "generic" is not advisable because nested child classes will look weird when referenced (they use the parent type): GenericActionType.Dialer(...)
• "Type" doesn't seem appropriate here because this is already a type, and that type represents an action, not an action type. If it were an action type you wouldn't have data associated with it like those urls
Maybe Action.Dial would look better

[Colton Idle]

True. I guess I'm trying to not interfere with other classes called Action. Great feedback though. Thanks

[Joffrey]

Yeah I guess to avoid conflicts you might want to find a more precise name than Action but these "generic" and "type" words didn't give more precision IMO. Maybe some words from the domain would help, like UserAction or something

[Luke]

Also, tiny improvement, unless GenericActionType defines something for the subclasses, consider using sealed interface

[Colton Idle]

ooh. good point too @Luke

[Adam Powell]

you kind of have to make at least one really good mess with sealed classes and way over-modeling a domain to get a feel for when they're the right tool 🙂

[Adam Powell]

(says someone who spent part of last weekend ripping out and replacing one such hierarchy from a hobby app)

[Jason5lee]

If you know about design patterns, this is what visitor pattern tries to do in a awkward way.