returning multiple values in Java

Question

Preamble: I am aware of using a list or other collections to return a result but then I have to go through the list plucking the results out: see 2nd example

Preambl

Answer 1

Using a generic tuple class is the closest I can imagine. To give an idea, such general purpose class for three return values could look something like this:

public class T3 {
    A _1;
    B _2;
    C _3;
    T3(A _1, B _2, C _3) {
        this._1 = _1;
        this._2 = _2;
        this._3 = _3;
    }
}

This allows a one statement constructor on the callee side, for example:

public T3 getValues() {
    return new T3("string", 0, 'c');
}

but no holder instance construction by the callee is to be done.

Each number of return values needs a tuple-class of its own. There might be something like that provided in the Functional Java library. For reference, here's an N-Tuple implementation.

For the two-valued case java.util.AbstractMap.SimpleEntry would do:

return new SimpleEntry("string", 0);

Anyhow, I see two important points to consider for multiple return values:

1. Typed return values
2. Pointing out the meaning of each return value

As boring as it is, I'd recommend creating a separate class to hold all the response values and declare that as the method return type. That way the meaning of each value can be highlighted.