Check if returned value is not null and if so assign it, in one line, with one method call

Question

Java is littered with statements like:

if(cage.getChicken() != null) {
    dinner = cage.getChicken();
} else {
    dinner = getFreeRangeChicken();
}

Which takes two calls to getChicken() before the returned object can be assigned to dinner.

This could also be written in one line like so:

dinner = cage.getChicken() != null? cage.getChicken() : getFreeRangeChicken();

But alas there are still two calls to getChicken().

Of course we could assign a local variable then use the ternary operator again to assign it if it is not null, but this is two lines and not so pretty:

FutureMeal chicken = cage.getChicken();
dinner = chicken != null? chicken : getFreeRangeChicken();

So is there any way to say:

Variable var = some value if some value is not null OR some other value;

And I guess I'm just talking syntax here, after the code is compiled it probably doesn't make much difference how the code was written in a performance sense.

As this is such common code it'd be great to have a one-liner to write it.

Do any other languages have this feature?

Answer 1

Java lacks coalesce operator, so your code with an explicit temporary is your best choice for an assignment with a single call.

You can use the result variable as your temporary, like this:

dinner = ((dinner = cage.getChicken()) != null) ? dinner : getFreeRangeChicken();

This, however, is hard to read.