CODEWITHSUNDEEP
java
Matias Faure
Matias Faure

Reputation: 842

How do I restrict the range permitted for the int argument of a method

Say I have a method:

public void method(int i) {
    this.value =+ i;
}

How can I restrict i to a value greater than x? I understand this can be done outside the method but I would prefer to condition it in the constructor. Would it be something like:

public void method(int i; i > x){...};

Sorry for not testing this myself, I came up with it as I wrote my query.

Upvotes: 1

Views: 3574

Answers (3)

JB Nizet
JB Nizet

Reputation: 691845

You document the method, and throw an exception if the caller doesn't respect the contract. 

/**
 * Does something cool.
 * @param i a value that must be > x
 * @throws IllegalArgumentException if i <= x
 */
public void method(int i) {
    if (i <= x) {
        throw new IllegalArgumentException("i must be > x");
    }
    this.value += i;
}

Upvotes: 7

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 280030

That are no built-in preconditions for method (or constructor) arguments. Either check them at the calling site or within the method (or constructor). You have two options: throw an exception within the method or don't call the method.

Upvotes: 2

rgettman
rgettman

Reputation: 178263

There is no syntax in Java that can restrict the range of a parameter. If it takes an int, then all possible values of int are legal to pass.

You can however test the value with code in the method and throw an IllegalArgumentException if i is not greater than x.

Upvotes: 9

Related Questions