How to change DecimalFormat behavior based on input length?

Question

I am using the following DecimalFormat template:

 // Use ThreadLocal to ensure thread safety. private static final ThreadLocal <NumberFormat> numberFormat = new ThreadLocal <NumberFormat>() { @Override protected NumberFormat initialValue() { return new DecimalFormat("#,##0.00"); } }; 

This performs the following conversions:

 1 -> 1.00 1.1 -> 1.10 1.12 -> 1.12 

Now I have an additional requirement.

 1.123 -> 1.123 1.1234 -> 1.123 

This means that when

• less than two decimal places, I will "work out" up to two decimal places.
• there are exactly two or three decimal places, I won’t do anything.
• there are more than three decimal places, I truncate to three decimal places.

Can this behavior be specified with the DecimalFormat class?

Answer 1

 DecimalFormat("#,##0.00#") 

Answer 2

Have you tried changing the RoundingMode of your DecimalFormat instance?

A call to setRoundingMode(RoundingMode.FLOOR) should do the trick

See also setRoundingMode (java.math.RoundingMode)