You can also check if it's null when calling the method.

# getting-started

[karelpeeters]

You can also check if it's null when calling the method.

[davidase]

it's an information-dump page where i just list whatever information that is available for an object

$msg.get("PAYMENT_DATE", $transaction.paidDate)
$msg.get("PAYMENT_METHOD", $transaction.paidWith)
$msg.get("PAYMENT_AMOUNT", $transaction.totalAmountPreVat, $transaction.currency)

i don't really care if anything is null

[davidase]

i'm not really looking for alternate solutions, the approach i have currently works well for java

[davidase]

i was just wondering if there was a nicer way of writing the function

[karelpeeters]

Then what did you mean with "varargs can't be null"? They certainly can, if you give them a nullable type like in @menegatti's example.

[davidase]

then you'll have to pass an array of nulls, you can't pass just a singular null value

[karelpeeters]

Can you give some example of how you want this to work?

get("key", "a", "b", "c")
get("key", "a", null)
get("key", null, "a")
get("key", null)
get("key")
get("key", *arrayOf("a", null))
get("key", *arrayOf<String>())

All of those would work with the vararg one.

[davidase]

hmm, get("key", null) won't work for me

[davidase]

fun get(key: String, vararg args: Any?): String {
    return MessageFormat.format(get(key), *args)
}

Parameter specified as non-null is null: method util.MessageBundle.get, parameter args

[karelpeeters]

Huh that is strange, I wonder if it's intended.

[davidase]

i made a new project and just ran your snippet, there everything works 🤔

[karelpeeters]

Do both projects have different compiler versions?

[davidase]

get is being called from apache velocity in my original project

[davidase]

not sure why that would matter though

[karelpeeters]

Did you actually run the broken one or is that just Idea complaining?

[davidase]

i ran it

[karelpeeters]

Compiler versions?

[davidase]

org.apache.velocity.exception.MethodInvocationException: Invocation of method 'get' in  class util.MessageBundle threw exception java.lang.IllegalArgumentException: Parameter specified as non-null is null: method util.MessageBundle.get, parameter args at /velocity/views/data-dump.vm[line 5, column 41]
Caused by: java.lang.IllegalArgumentException: Parameter specified as non-null is null: method util.MessageBundle.get, parameter args

[karelpeeters]

Right that's just Kotlin's build-in runtime null checking complaining.

[davidase]

why would it complain when calling the function from velocity, but not from a fun main ?

[davidase]

kotlin 1.1.2-2 
target jvm1.8 
javac 1.8.0_101

[benleggiero]

Oh yeah in Java, there's no obvious way to distinguish get("key", {1, 2, 3}) from get("key", 1, 2, 3), so in Java, get("key", null) is like get("key", *null) in Kotlin.

Assuming the calling code is Java

[karelpeeters]

Ah that could be the difference, is the calling code Java?

[davidase]

@benleggiero thanks, does that mean i'm stuck with this?

fun get(key: String, args: Array<Any?>?): String {
    if (args == null) return MessageFormat.format(get(key), args)
    return MessageFormat.format(get(key), *args)
}

[davidase]

@karelpeeters yes, sorry if i failed to make that clear

[davidase]

the function is being called from apache-velocity, a java-based template engine

[karelpeeters]

You can overload it with a version that takes a single extra parameter and calls the other one.

[davidase]

🤔