How to add only non-null item to a list in Groovy

Question

I want to add non null items to a List. So I do this:

List<Foo> foos = []
Foo foo = makeFoo()
if (foo)
    foos << foo

But is there a way to do it in a single operation (without using findAll after the creation of the list). Like:

foos.addNonNull(makeFoo())

Answer 1

Another alternative is to use a short circuit expression:

foo && foos << foo

The foo variable must evaluate to true for the second part to be evaluated. This is a common practice in some other languages but I'd hesitate to use it widely in groovy due to readability issues and conventions.

Answer 2

No, you'd need to use an if, or write your own addNonNull method (which just uses an if)

Also:

if( foo ) {

probably isn't enough, as this will skip empty strings, or 0 if it returns integers

You'd need

if( foo != null ) {