customer balance scale as the exponent of it's currency

Question

i have 2 classes under java hibernate project

currency class with variable (exponent) with (BigDecimal) DataType

&

customer class with variable (balance) with (BigDecimal) DataType

i want to set scale of balance as exponent

example:

1) if exponent = 2, and balance = 230.1340098 then balance must be 230.13
2) if exponent = 1, and balance = 230.1340098 then balance must be 230.1
3) if exponent = 3, and balance = 230.1340098 then balance must be 230.134
4) if exponent = 0, and balance = 230.1340098 then balance must be 230
....
....
....

how can i do this?

what's i mean i want to put the customer balance scale as the exponent of his currency

Note: i try BigDecimal.setScale() but this method required constant integer field dataType where exponent is BigDecimal and variable

Answer 1

BigDecimal#setScale(...) should work:

BigDecimal balance = BigDecimal.valueOf(  230.1340098 );  
BigDecimal exponent = new BigDecimal( 2 ) ; //randomly chosen
BigDecimal rounded = balance.setScale( exponent.intValue(), RoundingMode.HALF_UP ) ); //you can use another rounding mode

This yields rounded = 230.13.