Utility method to convert Boolean into boolean and handle null in Java

Question

Is there a utility method in Java which converts Boolean into boolean and automatically handles null reference to Boolean as false?

Edrick

Ermm ... it is one line of code ... – Eth

possible duplicate of Booleans, conditional operators and autoboxing – Tropic

@StephenC Yeah ..but OP might searching for a smart line of code ;) (look at skeets solution) – Irregularity

Answer 1

How about:

boolean x = Boolean.TRUE.equals(value);

? That's a single expression, which will only evaluate to true if value is non-null and a true-representing Boolean reference.

Deal

Answer 2

On java 8 you can do:

static boolean getPrimitive(Boolean value) {
        return Optional.ofNullable(value).orElse(false);
}

You can also do:

static boolean getPrimitive(Boolean value) {
        return Boolean.parseBoolean("" + value);
}

Muddle

These both allocate an unnecessary object. Jon Skeet's answer doesn't. – Selfesteem

both are 'valid' and memory overheads are negligible.(The first one is simply an optional return, if its really so bad?) I am very well aware of 'jon skeets' answer, but this is more to demonstrate what is possible, (more so with OP's context of automatically handling null reference for Boolean). – Muddle

One unnecessary object allocation per call is not negligible in code that is called, in a practical use case, once per boolean column, per row, per database fetch. Yes, the JVM might be able to optimize away the Optional via escape analysis. But it also might not. Why use a longer, less clear, allocating idiom when a shorter, clearer, non-allocating alternative exists? – Selfesteem

with all due respect, please refer the OP, it didnt ask for most optimum way to do it, but the way in which null is handled automatically. Please take things in context. By your reasoning I suppose you are advocating not to use Optional? PS: The accepted answer is the best fit. – Muddle

I have no problem with Optional when used as intended, a return type for methods which may or may not return a result. – Selfesteem

Answer 3

I don't know whether it exists or not. I'd write a one liner like:

public static boolean getPrimitiveBoolean(Boolean bool) {    
   return bool == null ? false : bool.booleanValue();
}

Irregularity

Answer 4

Are you looking for a ready-made utility ? Then I think Commons-Lang BooleanUtils is the answer. It has a method toBoolean(Boolean bool).

Depict

Answer 5

If you're golfing, an explicit null check followed by automatic unboxing is shorter than the canonical answer.

boolean b=o!=null&&o; // For golfing purposes only, don't use in production code

Selfesteem

Answer 6

This would be a method you could write that would do the trick. This would return false if the Boolean is null.

public static boolean toBooleanDefaultIfNull(Boolean bool) {
    if (bool == null) return false;
    return bool.booleanValue();
}

Galley

The return bool.booleanValue() ? true : false; is pretty useless, just do return bool.booleanValue() ;) – Pagination

Skeet's answer is much better than this, but I'll change mine with your suggestion anyways. – Galley

Answer 7

Alternative:

boolean isBooleanObjectTrue = booleanObject.booleanValue();

See usage:

public static void main(String[] args) {
    Boolean booleanObject = Boolean.TRUE;
    boolean isBooleanObjectTrue = booleanObject.booleanValue();
    System.out.println(isBooleanObjectTrue); // prints: 'true'

    booleanObject = Boolean.FALSE;
    isBooleanObjectTrue = booleanObject.booleanValue();
    System.out.println(isBooleanObjectTrue); // prints: 'false'
}

Pantisocracy