Hey guys, is it ok to use kotlin getter like that (theoretical example): ```val isTooLate: Boolean...

# android

[Radoslaw Juszczyk]

Hey guys,

is it ok to use kotlin getter like that (theoretical example):

val isTooLate: Boolean
   get() = System.currentTimeMillis() > someTimestamp

I find it confusing that hovering over it in the IDE gives:

public final val isTooLate: Boolean

which gives an impression that this value is going to be always the same - but it's not.

[Vitor Hugo Schwaab]

By final the IDE means that you are not able to set it to a different value, i.e. you can't call isTooLate = false or isTooLate = true.
Its definition is final, even thought its result may change.

[Radoslaw Juszczyk]

you are right it is about forbidding to override it!

[Radoslaw Juszczyk]

but reading some answers on stackoverflow on a val bit of it:

val is like Final variable and it's known as immutable in kotlin and can be initialized only single time.

They point out that it is immutable but in reality it is just a read only *var*iable - so it seems that ppl wrongly expect it to be immutable

Regarding the example I provided - in that situation, would you use val with get {} or would you use a function fun isTooLate(): Boolean ?

[Radoslaw Juszczyk]

and that raises another question:

when to use argument-less function syntax?

[Robert Williams]

That's more a style choice but would recommend following kotlin's own guidelines: https://kotlinlang.org/docs/coding-conventions.html#functions-vs-properties

[Robert Williams]

Clearly the third point (returns the same result over invocations if the object state hasn't changed) doesn't hold here so a fun makes more sense

[Robert Williams]

In fact you actually have a hidden external dependency in System.currentTimeMillis()

[Robert Williams]

May be clearer and better for testing to have something like

fun isTooLate(currentTime: Long = System.currentTimeMillis())

[Radoslaw Juszczyk]

thanks, this coding-convetions is a very useful link!

[Radoslaw Juszczyk]

yea, i know it can be clearer, i wanted to give an example where the returned value changes over time based on external events