Null safe not allowed in loop

[shoon]

The following syntax does not translate over from Groovy (where it does work)

Groovy:

{list user.keyStore?.keys}

...

{/list}

Rythm:
@for(user.keyStore?.keys) {
...
}

Error:
Syntax error on token "?", delete this token

What is the correct method for null safe checks inside of a loop?

[greenlaw110]

null safe is not supported in @for loop. And it's recommend not to use null
value with any collection type, instead an empty collection should be used
instead. see
http://www.coderanch.com/t/445793/java/java/Returning-null-returning-empty-collection,
For your specific case, you can use @for(user.keyStore == null ?
Map.emptyMap().keys() : user.keyStore.keys())

[shoon]

Sorry for not providing more details... the keyStore is a single object @reference and keys is the collection. Keystore is optional (thus the null check) whereas the keys collection is never null.

[greenlaw110]

If this case you still need to use @for(user.keyStore == null ?
Map.emptyMap().keys : user.keyStore.keys) for now. Movingforward I will
provide a configuration item say "rythm.nullsafe.enabled", and suppress all
NPE in the template, so that you can use:

@for(user.keyStore.keys) {
...
} else {
@// if keyStore is null or keys is empty all goes here
...
}

[shoon]

That sounds like a great solution. Thank you.