Compare if BigDecimal is greater than zero

Breaking down BigDecimal comparison

Every compareTo call will return three possible outcomes:

• 1 if the BigDecimal value is greater than the argument.
• 0 if the BigDecimal value is equal to the argument.
• -1 if the BigDecimal value is less than the argument.

Armed with these possible results, we can put together a simple comparison in a single line:

if (value.compareTo(BigDecimal.ZERO) > 0) {
    // value is greater than zero, so pop the champagne! 🍾
}
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Inside the world of BigDecimal comparison

It's all about precision

BigDecimal provides an arbitrary-precision numeric representation, making it a lifeline for scenarios needing an exact representation of numbers such as monetary calculations.

The "equals" trap

Avoid the equals method for zero comparisons as it compares the scale (2.0 is not equals to 2.00). So it's more of an "equals*" method, terms and conditions apply.

How about "signum()"?

The signum method can quickly determine the sign of the number and returns -1, 0, or 1. A handy shortcut for checking if the value is positive:

boolean isPositive = value.signum() > 0;
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But why not "abs()"?

The abs method is a bit of a misdirection as it's meant for absolute value calculation, not comparisons. For a greater-than-zero query, stick to compareTo.

Mind the pitfalls and edge cases

Mismatched scales

Misinterpretations can arise when comparing BigDecimal values with different scales. Always ensure scale normalization or lean on compareTo to handle it for you.

Precision lost in transit

Operations like divide could lead to values with repeating decimals. Control the scale by using setScale and a rounding mode to prevent this.

Immutable objects

BigDecimal is immutable. Methods such as setScale & abs return new instances of the value rather than modifying the original.

"compareTo" or "signum": A choice of weapons

The "compareTo" arsenal

• Opt for "compareTo" for detailed comparison results (greater, equal, less).
• Employ "compareTo" when multiple conditions depend on the exact relationship.

The "signum" toolkit

• Reach for "signum" for quick sign checks (positive, zero, negative).
• Use "signum" for less bytecode instructions and a faster runtime.

Note on performance

Most of the time, the performance difference is minuscule and thus inconsequential. Remember, readability and correctness triumph over micro-optimizations.