CODEWITHSUNDEEP
java
Mykhaylo Adamovych
Mykhaylo Adamovych

Reputation: 20966

How to check whether an Integer is null or zero in Java?

Is there more concise way to write: 

if (myInteger != null && myInteger != 0) { ... }

For example, for Strings you can use StringUtils.isBlank()

Upvotes: 45

Views: 136884

Answers (8)

SHUBHAM RUHELA
SHUBHAM RUHELA

Reputation: 17

private boolean isNotNullAndZero(Long num){
        return Optional.ofNullable(num).orElse(0L) != 0L ? true:false;
    }

Upvotes: 0

ITisha
ITisha

Reputation: 964

There is also a nullsafe way to do it like:

Long val = null;
if( val == Long.valueOf( 0 ) ) {...}

or

if( Objects.equals( val, 0L ) ) {...}

Upvotes: 3

cokekutu
cokekutu

Reputation: 51

private boolean isNullOrZero(Integer i){
     return i == null || i.intValue() == 0;
}

For some other types:

i.longValue() == 0 for Long

i.doubleValue() == 0 for Double

i.shortValue() == 0 for Short

i.floatValue() == 0 for Float

Upvotes: 2

Marcos Echagüe
Marcos Echagüe

Reputation: 597

I created a helper method that maybe can help you, it uses reflection so you have to think if is necessary to use it, also you need java 8.

The method is for all java numbers:

 public class NumberUtils {

    private NumberUtils(){
    }

    public static  < T extends Number>  T getNumberOrZero(T number, Class<? extends Number> clazz) {
        return Optional.ofNullable(number)
                .orElse(getZeroValue(clazz));
    }

    @SuppressWarnings("unchecked")
    private static < T extends Number> T getZeroValue( Class<? extends Number> clazz){
        try{
            Constructor<? extends Number> constructor = clazz.getDeclaredConstructor(String.class);
            return (T) constructor.newInstance("0");
        }catch (ReflectiveOperationException e) {
            throw new IllegalArgumentException("Can't get zero value ", e);
        }
    }
}

You can call in this way:

Integer myNumber = NumberUtils.getNumberOrZero(someIntegerThatCanBeNull, Integer.class);

I hope this can help you.

Upvotes: 1

Yoory N.
Yoory N.

Reputation: 5474

Since StringUtils class is mentioned in the question, I assume that Apache Commons lib is already used in the project.

Then you can use the following:

if (0 != ObjectUtils.defaultIfNull(myInteger, 0)) { ... }

Or using static import:

if (0 != defaultIfNull(myInteger, 0)) { ... }

Upvotes: 19

Florian Albrecht
Florian Albrecht

Reputation: 2326

With Java 8:

if (Optional.ofNullable(myInteger).orElse(0) != 0) {
  ...
}

Note that Optional may help you to completely avoid the if condition at all, depending on your use case...

Upvotes: 38

AxelH
AxelH

Reputation: 14572

I would use a ternary condition for this. Something like :

public static boolean isNullorZero(Integer i){
    return 0 == ( i == null ? 0 : i);
}

This is not readable, I agree ;)

Upvotes: 6

CraigR8806
CraigR8806

Reputation: 1584

Depending on your implementation of myInteger (i.e. if the Integer property within myInteger is the box type Integer or the unboxed primitive int), you may only have to write one conditional.

Integers are actual objects, which means they have the ability to be null. That being said they can also hold 0 as a value. So, in this case you would have to make both checks.

int is a primitive and cannot hold the value of null. In this case you would only have to check if your int property is not equal to 0.

Upvotes: 0

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