Using Javascript to change Aggregation Builder Expression

Can anyone tell me how to change the aggregation expression from the Aggregation Builder using Javascript?

I have a table with a group defined in the footer and a column that was defined using Aggregation Builder to have a function applied to an expression. E.g.

Aggregation Builder
Display Name: series1Agg
DataType: Integer
Function: COUNTDISTINCT
Expression: row["series1"]*2
Aggregate On: Group myGroup

What I am trying to do is to dynamically change the EXPRESSION using Javascript - anyone know how I can do that?

The XML of the report design for the expression looks like this:
<list-property name="arguments">
<structure>
<property name="name">Expression</property>
<expression name="value">row["series1"] * 2</expression>
</structure>
</list-property>

How can I access the contents of this stucture using Javascript??

Ok, so I have been able to use Javascript to change the aggregation function (by looking at the XML and guessing mostly), using this:

this.getDataBindings()[2].getStructure().setProperty("aggregateFunction", "Sum");

The XML for this was simpler:
<property name="aggregateFunction">COUNTDISTINCT</property>

Thanks in advance for any help,

dan

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Comments

mwilliams

Hi Dan,

I have tried several things and have not been able to find out how as of yet. If I figure something out, I will post it in here.

djatnieks

Thanks for looking into this Michael. Here's what I finally ended up with - there must be a better way, especially a better way to access the data binding for the column.

I put this code in the onPrepare() for my table. I couldn't find a way to access the data binding from the column cell level.

importPackage(Packages.org.eclipse.birt.report.model.api.elements.structures);

// Create a new aggregation argument called Expression. There is one already
// existing in the rptdesign - adding a new one seems to either replace or
// be processed instead of the original.
var arg = new AggregationArgument();
arg.setName("Expression");

//Create the new expression value
var exprValue = "row["series1"] / 100" ; // this is actually dynamic based on parms not shown here
arg.setValue(exprValue);

// The already existing expression argument should probably be removed,
// but I don't know how to access it. The remove() method seems to
// require already knowing the argument being removed, but I could not
// find a way to get that.
//this.getDataBindings()[2].getStructure().removeArgument(existingarg);

// Add the new agg argument to the correct table column structure.
// If there is a better way to do this, I would be glad to learn about it!
this.getDataBindings()[2].getStructure().addArgument(arg);

// Now there are 2 arguments, but Birt seems to only use the newly
// added one, so it works.