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?
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.