Adding BigDecimal.valueOf(float val) constructor

[Raffaello Giulietti]

Hi Jan,

to add to the other replies, it's a bit unfortunate that the doc of 
valueOf(double) suggests that this method should preferably be used to 
convert _float_ values as well.

You are right that your valueOf(float) would be a better fit, but again, 
that's hardly possible for source compatibility reasons after more than 
20 years of valueOf(double) existence. Recompiling an existing source 
code that happens to invoke valueOf(double) with a float argument would 
suddenly change behavior for no apparent reasons.

One way out would be to add your method with a different name, like 
valueOfFloat(float) or similar, which would however break a long naming 
tradition of valueOf() conversion methods.


Greetings
Raffaello



On 2025-01-23 22:20, Jan Kowalski wrote:
> Hi!
> 
> I’m currently working on a project that heavily relies on float values, 
> and we occasionally use BigDecimal for more precise mathematical 
> operations. However, I’ve noticed that the current BigDecimal 
> constructor implementation only supports double, which can lead to 
> unintentional type conversion and precision loss when creating a 
> BigDecimal from a float.
> 
> The documentation suggests using BigDecimal.valueOf(double val) as the 
> preferred method for converting double or float values to BigDecimal, 
> but since method takes double as an argument, it leads much more often 
> to precision loss when float is passed.
> 
> For example:
> 
> - BigDecimal.valueOf(0.1d) correctly produces 0.1.
> 
> - However, BigDecimal.valueOf(0.1f) produces 0.10000000149011612, which 
> introduces unwanted precision artifacts.
> 
> What would you think about introducing a static factory method 
> specifically for float values, such as:
> 
> public static BigDecimal valueOf(float val) {
>      return new BigDecimal(Float.toString(val));
> }
> 
> This addition should improve usability and ensure that float values are 
> handled more precisely within the BigDecimal API