JSF DataTable Not Updated on Action Event

Question

I am building out an order management application and am running into a problem where I cannot get changes to the information in a data table.
My form looks like the following
First Name: Emmet
Last Name: Brown
Line Item     Product ID     Description        Quantity
1             FUELPLTNM      Plutonium Tablet   1
2             FLXCAP88       Flux Capacitor     1
3             DELOREAN       Delorean           1
4             CLRADSUXL      Radiation Suit     1Everything is displayed properly and I have defined the button to save the form changes using the following tag
<h:commandButton action="#{order.save}" value="Save"/>If, when editing the form in the browser, I go to the row with "Plutonium Table" in the 'Description' column, change the value in the 'Quantity' column from "1" to "2", and click on the 'Save' button, the changes to the dataModel are not accessible.
If I look at the contents of my HTTP POST transaction when I click on the 'Save' button, I can see that all the table data elements are present (including the changes); however, I can't figure out how to access the table data when I'm processing the action.
For the time being, I've taken what I would characterize as a brute force hack to accomplish my goals. I'm obtaining a reference to the RequestParameterMap and am parsing out the values for the lineItems which I am then using to update the data model. I know there has to be a more elegant solution.
Any help/guidance would be appreciated.
Message was edited by: Derek Berube

Answer 1

I really need to spend a little more time browsing over the forums and looking for responses.
Here is what I actually ended up doing. This is a total hack-job, but I needed to get some things done. Of course now I have another "problem" which is forcing me to revisit my hack - you know what they say about shortcuts.
Essentially, when I needed to reconstitute the "child table", I was grabbing all the information from the ExternalContext. Since I was naming all of the elements in my JSP page, I knew what to look for.
Here is the code that I'm using. There is a getProperty helper method that I'm using. It follows the harvestLineItems() listing. For the most part, this was working great; however,
private static List<LineItemHandler> harvestLineItems() {
     log.trace("[BEGIN]");
     boolean work=true;
     int elementNum=0;
     ExternalContext eCtx=null;
     FacesContext ctx=null;
     List<LineItemHandler> lineItems=null;
     Map<String,String> parameters=null;
     String value=null;
     String property=null;
     LineItemHandler lineItem=null;
     // Obtain a reference to the Faces Context
     ctx=FacesContext.getCurrentInstance();
     eCtx=ctx.getExternalContext();
     parameters=eCtx.getRequestParameterMap();
     // Check to see if the trace mode is set.
     if (log.isTraceEnabled()) {
          // Logging is enabled, so dump the request parameter map.
          if (parameters.size() > 0) {
               log.trace("Request Parameter Map");
               for (String key: parameters.keySet()) {
                    log.trace(key+"="+parameters.get(key));
               } // END for (String key: parameters.keySet())
          } else {
               log.trace("The request parameter map contains no data.");
          } // END if (parameters.size() > 0)
     } // END if (log.isTraceEnabled())
     // Prepare the list to store line items
     lineItems=new ArrayList<LineItemHandler>();
     // Start with the first lineItem
     elementNum=0;
     while (work) {
          // Get the line item property
          property=getProperty("lineItem",elementNum);
          value=parameters.get(property);
          // The LineItem parameter was found, so get the rest.
          if (value != null) {
               // Handle the lineItem
               lineItem=new LineItemHandler();
               // Add the line item to the list...
               lineItems.add(lineItem);
               lineItem.setItemNumber(Integer.parseInt(value));
               log.trace("itemNumber: "+value);
               // deleteFlag
               property=getProperty("deleteFlag",elementNum);
               value=parameters.get(property);
               if (value==null) {
                    lineItem.setDeleteFlag(false);
                    log.trace("deleteFlag: false");
               } else {
                    lineItem.setDeleteFlag(Boolean.parseBoolean(value));
                    log.trace("deleteFlag: "+value);
               // productId
               property=getProperty("productId",elementNum);
               value=parameters.get(property);
               log.trace("productId: "+value);
               try {
                    lineItem.setProductId(value);
               } catch (ProductIdTooLongException ex) {
                    log.error("ProductIdTooLongException",ex);
                    try {
                         lineItem.setProductId("");
                    } catch (ProductIdTooLongException ex1) {
                         log.error("This shouldn't happen.",ex1);
               // Description
               property=getProperty("productDescription",elementNum);
               value=parameters.get(property);
               log.trace("productDescription: "+value);
               lineItem.setDescription(value);
               // Quantity
               property=getProperty("quantity",elementNum);
               value=parameters.get(property);
               log.trace("quantity: "+value);
               lineItem.setQuantity(Integer.parseInt(value));
          } else {
               // The lineitem parameter is not found, so time to stop working
               work=false;
          // Increment the element number
          elementNum++;
     } // END while (work)
     log.trace("[END]");
     return lineItems;
private static String getProperty(String property, int number) {
     log.trace("[BEGIN]");
     StringBuilder propertyBuilder=new StringBuilder(128);
     propertyBuilder.append("order:tblLineItems:");
     propertyBuilder.append(number);
     propertyBuilder.append(":");
     propertyBuilder.append(property);
     log.trace("[END]");
     return propertyBuilder.toString();
}