RowIterator

Question

Hi,
I am trying to iterate through the rows in a detail entity to determine what the maximum number is in a field. The number in each row represents its position in the detail set. When I get the max I will return it to the create(Attributes) method of the detail entity and bump it by one to set its position value when the new record for the entity is created via the insert button in the navigation bar.
I defined a non-persistent field in the master entity and am using its get function to do the iteration. In my test case I have 3 existing records and the new empty record created by pressing the insert button. When I try to iterate through the detail records, on the second time through the loop the next() returns a null the second time through the loop.
Here is the code. I have left some debugging statements in so I know what values are.
public Number getComorbidsmaxrow() {
// return (Number)getAttributeInternal(COMORBIDSMAXROW);
/* Get an iterator over the number of comorbid records */
RowIterator comorbids = this.getComorbids();
int rowSlot = comorbids.getCurrentRowSlot(); // rowSlot is equal to 2
int numRows = comorbids.getRowCount(); // numRows is equal to 4
comorbids.reset();
/* diagnosis refers to each item within Comorbids */
ComorbidsImpl diagnosis;
/* maxRow is the maximum row number found in the Comorbids set */
Number maxrow = new Number(0);
/* rowNum is the number of the current diagnosis */
Number rowNum;
try {
// Get the next diagnosis, if comorbids.hasNext() is false then we have reached
// the end of the iterator
while (comorbids.hasNext()){
diagnosis = (ComorbidsImpl) comorbids.next();
rowNum = diagnosis.getComorbidno(); //first time through, rowNum is equal to null, I believe because the first record is the one being inserted; second time program jumps to the catch after attempting the next() in the previous statement.
int rowIndex = comorbids.getCurrentRowIndex();
if (rowNum != null) {
if (maxrow.intValue() < rowNum.intValue()) maxrow = rowNum;
catch (Exception ex) {
return maxrow;
return maxrow;
I used the Order/lineItem (traversing entity objects) and the calcDeptTotal (subscribing to an event) examples as models.
Thanks for any help.
Peter

Answer 1

Not entirely sure what you mean...but this might helpful.
This is meant for a "Data Action" on your struts diagram...you can do a lot there. It's a starting point...there are better ways to handle some of it.
protected void findForward(DataActionContext actionContext)
throws IOException, ServletException {
//This is a view object...javadoc it. You can create/edit, set where clauses, delete etc..
//Remember to call vo.executeQuery(); after you're done...
ViewObject vo = actionContext.getBindingContainer().getApplicationModule().findViewObject("SearchClassesView1");
//This is the request...you can pull parameters from the GET/POST for instance...to set where clauses or what have you.
HttpServletRequest request = actionContext.getHttpServletRequest();
String categories = request.getParameter("categories");
//This is the session...you can set and read attributes from their current session, among other things.
HttpSession session2 = actionContext.getHttpServletRequest().getSession();
//This sets which struts "forward" to follow at the end of the data action.
String target = "success";
actionContext.setActionForward(target);