Question

This method:

boolean containsSmiley(String s) {
    if (s == null) {
        return false;
    }
    else {
        return s.contains(":)");
    }
}

can equivalently be written:

boolean containsSmiley(String s) {
    if (s == null) {
        return false;
    }

    return s.contains(":)");
}

In my experience, the second form is seen more often, especially in more complex methods (where there may be several such exit points), and the same is true for “throw” as well as “return”. Yet the first form arguably makes the conditional structure of the code more explicit. Are there any reasons to prefer one over the other?

(Related: Should a function have only one return statement?)

Answer 1

In my experience, it depends on the code. If I’m ‘guarding’ against something, I’ll do:

if (inputVar.isBad()) {
    return;
}

doThings();

The point is clear: If that statement is false, I don’t want the function to continue.

On the other hand, there are some functions with multiple options, and in that case I would write it like this:

if (inputVar == thingOne) {
    doFirstThing();
} else if (inputVar == secondThing) {
    doSecondThing();
} else {
    doThirdThing();
}

Even though it could be written as:

if (inputVar == thingOne) {
    doFirstThing();
    return;
}
if (inputVar == thingTwo) {
    doSecondThing();
    return;
}
doThingThree();
return;

It really comes down to which way most clearly shows what the code is doing (not necessarily which bit of code is shortest or has the least indentation).