javabigdecimal

How to check if BigDecimal variable == 0 in java?

I have the following code in Java;

BigDecimal price; // assigned elsewhere

if (price.compareTo(new BigDecimal("0.00")) == 0) {
    return true;
}

What is the best way to write the if condition?

Solution

  • Use compareTo(BigDecimal.ZERO) instead of equals():

    if (price.compareTo(BigDecimal.ZERO) == 0) // see below

    Comparing with the BigDecimal constant BigDecimal.ZERO avoids having to construct a new BigDecimal(0) every execution.

    FYI, BigDecimal also has constants BigDecimal.ONE and BigDecimal.TEN for your convenience.

    Note!

    The reason you can't use BigDecimal#equals() is that it takes scale into consideration:

    new BigDecimal("0").equals(BigDecimal.ZERO) // true
new BigDecimal("0.00").equals(BigDecimal.ZERO) // false!

    so it's unsuitable for a purely numeric comparison. However, BigDecimal.compareTo() doesn't consider scale when comparing:

    new BigDecimal("0").compareTo(BigDecimal.ZERO) == 0 // true
new BigDecimal("0.00").compareTo(BigDecimal.ZERO) == 0 // true