Sum of a column content with tJasper component

[Gadje]

Hi everybody,

I would like to be able to do sum of a column content with iReport.

Here is my JRXML :

And here is my report where i would like to replace "null" values by sum of values above it :

is there somebody who know's how to do it ? Please.

Thanks.

[Gadje]

for those that will be interessed ...

I created a variable that i named "SOUS_TOTAL" for calculate the value "Total du bon" (as show in picture above with value "null") and whose the field is a Float type.

I set this variable property like that : 

Variable Class  : java.lang.Float

Calculation : Sum

Reset type : Group

Reset group : Groupe2

Increment type  : None

Variable Expression : $F{MONTANT_HT}

In the properties of the "SOUS_TOTAL" field of the previously created variable, I define the type as Float too.

For the top field ($F{Montant_HT}) in Detail band, i set it as a Float too (for the propertys of field and variable).

Now, my problem is that i dont catch the decimal after coma, while i see it if the fields type is String.

If somebody have an idea ...

[Gadje]

I found how to do what i need. I couldn't displayed the decimals because of point, it wasn't be treating correctly in Jasper iReport. i replaced it by comma in a tMap component and all worked perfectly.

All is solved.

If that can help somebody ...