Nicely written check for numbers that can be null in java

Question

I have an application where I need to handle a lot of numbers (Integers or Longs) comming from external sources.

The numbers can be null. In case they are null I always need to convert them to 0.

The problem seems trivial, but I don't want to write hundreds of times:

if (someNumber == null) {
    someNumber = 0;
} 

I don't like it for two reasons:

1. I don't like to write three lines of code for such simple task, especially because I need to do it many times
2. I don't like to to "mutate" someNumber (assign new value to someNumber variable)

I tried some other ways which can be seen here:

  public static void main(String[] args) {
    Integer zeroOrNull = new Random().nextBoolean() ? 0 : null;


    // version1: this is nasty (I already mentioned why)
    if (zeroOrNull == null) {
      zeroOrNull = 0;
    }

    // version2: this seems to much for so simple task...
    zeroOrNull = Optional.ofNullable(zeroOrNull).orElseGet(() -> 0);

    // version3: creating an util might be considerable. Is there already such predefined util ?
    zeroOrNull = MyUtil.getValueOrZero(zeroOrNull); // returns value or )

    System.out.println(zeroOrNull); // I want 0 here in case of null


  }

What is the preffered and nice way to do such "test for null/conversion to 0" ? Any chance to do this conversion implicitly?

Answer 1

Use i = (i==null)?0:i;

• one line check
• no method call
• plain and simple
• no additional dependency (unlike some other proposed solutions)

Place this check as close to your numbers source as possible, to avoid unnecessary duplications.

Answer 2

By creating overloaded versions of Null Checker

public static void main(String args[]) {

    Integer intObj = null;
    System.out.println("intObj : " + checkNull(intObj));

    intObj = 1122222;
    System.out.println("intObj : " + checkNull(intObj));

    Long longObj = null;
    System.out.println("longObj : " + checkNull(longObj));

    longObj = 666555556L;
    System.out.println("longObj : " + checkNull(longObj));

    System.out.println("*********With default value***********");

    intObj = null;
    System.out.println("intObj : " + checkNull(intObj, 1));

    intObj = 1122222;
    System.out.println("intObj : " + checkNull(intObj, 1));

    longObj = null;
    System.out.println("longObj : " + checkNull(longObj, 0L));

    longObj = 666555556L;
    System.out.println("longObj : " + checkNull(longObj, 0L));
}

static Integer checkNull(Integer obj) {
    if (obj == null)
        return 0;
    return obj;
}

static Long checkNull(Long obj) {
    if (obj == null)
        return 0L;
    return obj;
}

static Integer checkNull(Integer obj, int i) {
    if (obj == null)
        return i;
    return obj;
}

static Long checkNull(Long obj, long l) {
    if (obj == null)
        return l;
    return obj;
}

Answer 3

A simple solution would be to write a utility method like below:

public static Integer checkNullNumber(Integer i){
if(i == null)
   return 0;
return i;
}

Now you can use this method wherever you want like:

zeroOrNull = checkNullNumber(zeroOrNull);

Answer 4

I don't like to write three lines of code for such simple task, especially because I need to do it many times

if (zeroOrNull == null) zeroOrNull = 0;

I don't like to to "mutate" someNumber (assign new value to someNumber variable)

there is no way to change the null-value into a "0" without constructing a new Integer object that holds this "0" and this single line of code does just that