Defining a Custom XOR Operator in Java

General Discussions
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1

How can I define a Java XOR operator?

In Java, we already have logical AND, OR, and NOT operators, but there is no built-in XOR operator, according to Sun. I’ve created a method to mimic the XOR functionality as follows:

public static boolean logicalXOR(boolean x, boolean y) {
    return ( ( x || y ) && ! ( x && y ) );
}

I can call it like this:

boolean myVal = logicalXOR(x, y);

However, I would prefer to use an operator for XOR, like this:

boolean myVal = x ^^ y;

What should I do to define a custom Java XOR operator, or is there a way to achieve this kind of operator behavior in Java?

2

You’re already on the right track with the method approach. It’s clean, readable, and gets the job done. Here’s your original code with a minor refinement to improve naming clarity:

public static boolean logicalXOR(boolean x, boolean y) {
    return (x || y) && !(x && y); // XOR logic using OR and AND
}

You can use it like this:

boolean myVal = logicalXOR(x, y);

This method effectively mimics the java xor operation without introducing unnecessary complexity. However, it won’t give you a custom ^^ operator, as Java doesn’t allow operator overloading. But if clarity and simplicity are your goals, this is a solid approach.

3

If you want to leverage Java’s built-in java xor functionality, you can use the ^ operator, which is Java’s bitwise XOR. The challenge is that it only works with integers, but you can work around this by converting boolean values to 0 or 1 before applying XOR:

public static boolean logicalXOR(boolean x, boolean y) {
    return (x ? 1 : 0) ^ (y ? 1 : 0) == 1; // Using bitwise XOR for booleans
}

This method converts true to 1 and false to 0, applies the XOR operation using ^, and then checks if the result is 1.

Usage remains the same:

boolean myVal = logicalXOR(x, y);

This approach is efficient because it utilizes Java’s built-in java xor operator instead of manually implementing XOR logic with && and ||. However, it still doesn’t give you a ^^ operator, as Java doesn’t support custom operators.

4

Why You Can’t Have a Custom XOR Operator in Java (But a Cleaner Alternative)

Java doesn’t support defining custom operators like ^^. Operator overloading is not a feature in Java, so you’re limited to the existing built-in operators (+, -, *, &&, ^, etc.). Since ^^ isn’t one of them, there’s no direct way to introduce it.

However, if your goal is to make your code more readable and resemble an operator-like usage, you can use static imports to simplify method calls:

import static mypackage.MyClass.logicalXOR;

public class MyClass {
    public static void main(String[] args) {
        boolean x = true;
        boolean y = false;
        boolean myVal = logicalXOR(x, y);  // Feels more operator-like
    }
}

By statically importing the logicalXOR method, you avoid calling it with MyClass.logicalXOR(x, y) every time, making the code more concise while staying within Java’s constraints.

If Java ever introduces custom operators in the future (which seems unlikely), that would be the ideal solution. But for now, leveraging the java xor operator (^ for integers) and static imports is the closest you can get to the feel of a logical XOR operator in Java.