Rounding an integer to the nearest 100 or 1000

[Arjun_Naskar]

We have an attribute that represents the number of messages a particular user has sent. Because it seems weird to list the exact number, we want to round this to the closest hundred value. I assume velocity is the way to go and came up with the following but it failed to populate (just remained blank in the sample email send with a confirmed non null value)

#set ($rounded_number = $math.roundTo(2, ${lead.Message_Volume__c_contact}))

Additionally, over tens of thousands of messages, it would be helpful to have the usual (US format) commas in place for sets of 3 orders of magnitude.

Any advice or direction would be much appreciated.

[SanfordWhiteman · Accepted solution]

First: don't use ${formal} references in function calls. They lead to syntax errors because they can't be chained.

Second: $math.roundTo rounds to decimal places.  That's not the same as "closest hundred." (It also doesn't accept negative decimal places.)

Third: because of the oversimplification of $math.round (which always uses HALF_EVEN rounding) and Velocity's rather tragic verbosity you need this:

## supply your field and rounding scale
#set( $valueToRound = $lead.Message_Volume__c_contact )
#set( $toNearest = 100 )
##
## / --- begin rounding routine --- \ 
## No need to alter this code!
#set( $String = $context.getClass().forName("java.lang.String") )
#set( $NativeMath = $context.getClass().forName("java.lang.Math") )
#set( $BigDecimal = $context.getClass().forName("java.math.BigDecimal") )
#set( $BigDecimalFromString = $BigDecimal.getConstructor($String) )
#set( $pointsToMove = $NativeMath.log10($toNearest.doubleValue()).intValue() )
#set( $rounded = $BigDecimalFromString.newInstance(
    $valueToRound.toString()  
  ).movePointLeft(
    $pointsToMove
  ).setScale(
    0,
    $field.in($BigDecimal).ROUND_HALF_UP
  ).movePointRight(
    $pointsToMove
  )
)
## \ --- end rounding routine --- /
Rounded: ${rounded}

There are some alternate ways with $math.mod but none are as flexible, nor do they use real mathematical methods.

Fourth: the US locale commas are simple:

#set( $roundedWithCommas = $number.format('#,###', $rounded) )
${roundedWithCommas}

[SanfordWhiteman]

Arjun Naskar​ please return to this thread and read the supplied answer.

[SanfordWhiteman]

Again Arjun Naskar please return to this thread and read the supplied answer.

[Arjun_Naskar]

Very helpful. Thank you!