Strange Behavior in modifying the values in VO

Question

I have a VO based on EO from a custom table. The query is something like:
select EO.x, EO.y, (EO.x*EO.y) xy from EO
I have displayed the values from this VO on to a table in OAF page. All the columns are messageTextInput but the third column (xy) is read-only. I have written a fireAction to execute when x or y values are changed to update the xy value accordingly.
Code in CO:
if ("ValueChange".equals(pageContext.getParameter(EVENT_PARAM)))
OAApplicationModule am = pageContext.getApplicationModule(webBean);
am.invokeMethod("UpdateXY");
pageContext.forwardImmediately(<Same Page>, null,
OAWebBeanConstants.KEEP_MENU_CONTEXT,
null, null, true,
OAWebBeanConstants.ADD_BREAD_CRUMB_NO);
Code in AM:
public void UpdateXY()
xxVOImpl vo = getxxVO1();
Row r = vo.first();
while (vo.hasNext())
r = vo.next();
Object X = r.getAttribute("X");
String X_string = X.toString();
float X_value = Float.parseFloat(X_string);
Object Y = r.getAttribute("Y");
String Y_string = Y.toString();
float Y_value = Float.parseFloat(Y_string);
Float XY = new Float(X_value*Y_value);
r.setAttribute("XY",(Object)XY);
The problem is as follows. During the first time I try to update a value, the control goes through the logic and returns to the page but the XY value is not updated. But if i change a second value and tab out, the codes works and displays both the updated values of XY. From then on, the code is working fine.
I'm also not updating the first row and so I didnt perform any logic in AM for the first row.
Please help me out in finding out the reason for this strange behavior.

Answer 1

This nature is fine, basically initially your EO x and y columns are null and unless you do a commit, these values don't go in db. The third column will take x and Y coumns values from db and multiply and will get null.
To solve this issue, you get the values from VO columns x and y in PPR and and put x*y in the third column of Vo, IN THAT ROW.or you can directly get hold of the bean which hold the value of x*y and use setValue after getting x*y.
---Mukul