Why does setCellText vs setCellData behave differently?

Why does this alert work?

obj.setCellText(function(col,row) {
            if (this.getCellValue(15, row) == 'true'){
                alert("true");
              }
        }, 5);

And this one not?

obj.setCellData(function(col,row) {
            if (this.getCellValue(15, row) == 'true'){
                alert("true");
              }
        }, 5);

Nope! I just don't get it!!!

Can someone please explain to me the following:

I have a 'currency' column in my source data, unformatted. I would like to format it using:

var money = new AW.Formats.Number;  
            money.setTextFormat("#,###.##");

So I have to use setCellData, correct. I also would like to run a method on it to check whether I should possibly blank the cell, in order to do this I have to use setCellText!!! WTF? How am I supposed to do this?

This alerts BUT I have no formatting:

obj.setCellText(function(col,row) {
     alert(this.getCellText(5, row));
     }, 5);

This doesn't alert BUT I have formatting:

obj.setCellData(function(col,row) {
     alert(this.getCellText(5, row));
     }, 5);

Anyone? Alex?

When you assign something to the cell data property - the cell text property is adjusted to return the text calculated from the cell data (using cell format object). Here is the code -

function dataToText(i, j){
    var data = this.getCellData(i, j);
    var format = this.getCellFormat(i, j);
    return format ? format.dataToText(data) : data;
}

this.setCellText(dataToText);

You can use similar code to add your own processing on top of the standard dataToText transformation. Or you can make your own format object with custom dataToText method.