Java Class Constructor Parameters with range limits

Question

I\'m new to Java and I\'m asking this question just to help me better understand OOP.

Let\'s say I\'m defining a new Class called Hour. To instantiate this Class, we

Answer 1

Unfortunately Java unlike Pascal and other languages does not support range types. You can however use the other techniques.

The simplest way is to check the value in code.

class Hour {
    private final int h;
    public Hour(int h) {
        if (h < 0 || h >= 24) {
            throw new IllegalArgumentException("There are only 24 hours");
        }
        this.h = h;
    }
}

You can also use more sophisticated techniques. Take a look on java Validation API In this case your code will look like:

class Hour {
    @Max(23)
    @Min(0)
    private final int h;
    public Hour(int h) {
        this.h = h;
    }
}

But you will have to use one of available implementations of this API and invoke it.