Cleanest way to toggle a boolean variable in Java?

Question

Is there a better way to negate a boolean in Java than a simple if-else?

if (theBoolean) {
    theBoolean = false;
} else {
    theBoolean = true;
}
<         


        

Answer 1

If you use Boolean NULL values and consider them false, try this:

static public boolean toggle(Boolean aBoolean) {
    if (aBoolean == null) return true;
    else return !aBoolean;
}

If you are not handing Boolean NULL values, try this:

static public boolean toggle(boolean aBoolean) {
   return !aBoolean;
}

These are the cleanest because they show the intent in the method signature, are easier to read compared to the ! operator, and can be easily debugged.

Usage

boolean bTrue = true
boolean bFalse = false
boolean bNull = null

toggle(bTrue) // == false
toggle(bFalse) // == true
toggle(bNull) // == true

Of course, if you use Groovy or a language that allows extension methods, you can register an extension and simply do:

Boolean b = false
b = b.toggle() // == true