[flexcoders] converting a Java object into a chart dataprovider

[netdeep]

In the flex documentation, it shows how to easily create a chart with mxml and 
a static Array:

private var expenses:Array = [
        {Month:"January",Profit:2000,Expenses:1500,Amount:450},
        {Month:"February",Profit:1000,Expenses:200,Amount:600},
        {Month:"March",Profit:1500,Expenses:500,Amount:300},
     ];
<mx:ColumnSeries 
                xField="Month" 
                yField="Profit"
                displayName="Profit"
           />
           <mx:ColumnSeries 
                xField="Month" 
                yField="Expenses"
                displayName="Expenses"
           />

But I am reading my data from the database and want to pass the data via a java 
object.  But I don't know the number of fields at runtime.  So how do I assign 
the xFields and yFields since I won't be able to create a variable named 
"Month" or "Profit"?  I'll just have an array of floats or dates or whatever.  
Here's a start put I have no idea how to plug in the missing pieces or if 
another route would be preferable.

var lineSeries:LineSeries = new LineSeries();
BindingUtils.bindProperty(lineSeries, "dataProvider", ser, "javaArray");
// lineSeries.xField= ???
// lineSeries.yField= ???

 The data set is often quite large by the way.