Check if primitive has been set

Question

Given a very simple class:

class MyClass {
    int id;
    double value;

    MyClass(int id) {
        this.id = id;
    }

    void setValue(double v) {
        value = v;
    }

    boolean isValueUnassigned() {
        return value == 0;
    }
}

To check if value has not been assigned yet, is it OK if I just do return value == 0; since a double is 0 by default?

Answer 1

Found the cleanest and clearest way to express it:

class MyClass {
    int id;
    Optional<Double> value;

    MyClass(int id) {
        this.id = id;
        this.value = Optional.empty();
    }

    void setValue(double v) {
        value = Optional.of(v);
    }

    double getValue() {
        if (isValueUnassigned) {
            throw new RuntimeException("Value has not been assigned");
        }
        return value.get();
    }

    boolean isValueUnassigned() {
        return value.isEmpty();
    }
}