How to use Bitwise while setting properties

Sometimes we are faced with a situation, where a parameter can have multiple values, or even it can have combination of those values.

We have a few choices here, either we create multiple fields for each property, which is hard to scale but easier to understand.

Here is a code sample for that:

fun main() {
    order(true, true, false)
}

fun order(hasOrderedCheeseBurger: Boolean, hasOrderedFries: Boolean, hasOrderedSoda: Boolean) {
    println("Has Ordered CHEESEBURGER : ${hasOrderedCheeseBurger}"); // true
    println("Has Ordered FRIES : ${hasOrderedFries}"); // true
    println("Has Ordered SODA : ${hasOrderedSoda}"); // false
}

As you can see, we had to send 3 different parameters to know what this user had ordered and imagine, if, in future we need to add another item, let's say SANDWICH then we need to add another parameter.

Now, instead of passing multiple parameters, we can use bit manipulation to combine multiple parameters into a single parameter.

val CHEESEBURGER = 2; // 00000010
val FRIES = 4;        // 00000100
val SODA = 8;         // 00001000

fun main() {
    val ordered = CHEESEBURGER or FRIES;

    order(ordered)
}

fun order(what: Int) {
    val hasOrderedCheeseBurger = what and CHEESEBURGER == CHEESEBURGER;
    val hasOrderedFries = what and FRIES == FRIES;
    val hasOrderedSoda = what and SODA == SODA;
    println("Has Ordered CHEESEBURGER : ${hasOrderedCheeseBurger}"); // true
    println("Has Ordered FRIES : ${hasOrderedFries}"); // true
    println("Has Ordered SODA : ${hasOrderedSoda}"); // false
}

Here, bitwise allows us to add as many values as we need into a single parameter.

How to use Bitwise while setting properties

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