Dynamic DataTable without validation of the rest of the form

Question

I'm having a bit of trouble implementing a piece of functionality with JSF and I'm hoping someone here will have some insight into how to accomplish this.
I have a quite large form, with some fields requiring quite complex and expensive (both performance and actual money) validation (e.g. calling external web services, etc.). For the sake of the explanation, let's say the user enters details about himself, such as name, social security number, address, etc. Along with his details, he's to enter a limited subset of the details for each of his children (say name and social security number). We do not know at design time how many children the user has (obviously), so this part of the form has to be dynamically generated. Validation is performed on these children fields as well, so the user needs to be able to edit and remove children from the form.
Prior to JSF (straight JSP), I used DHTML and a naming scheme for these records with a custom setters in the backing beans.
What I have tried with JSF is to have a DataTable backed by a List. This table contains a single "Add Child" button which adds a new empty row to the table. There is also a "Remove" button for each row.
This works just great as long as I allow all other fields in the form to validate each time the user clicks the button. However, as I stated before, these validations are very very expensive (transaction based costs) . Additionally, I do not want to force the user to fill in all the other required fields (close to 40) before he can go on with the children.
Now, setting immediate="true" on the commandButton elements solves the problem of the other form fields validating. However, now the Children in the DataTable are never set because the update model values phase is never invoked, leaving me with empty input fields. I really do not care in this instance whether the data for the Children is valid or not, I just need to get them into the form.
I can think of at least three possible solutions:
1) Split up the form into several pages, like a wizard. However, the customer has rejected this option.
2) Somehow simplify the Children section by providing a single entry and a read-only table. This way I can use a simpler read-only table and I can extract the values from the request parameters directly. However, this complicated the editing of previously entered Children. To make things worse, the order of the children has to remain intact.
3) Create a custom HtmlInputText component that sets the values regardless of whether immediate="true" or "false".
It is this last option that I do not know how to do. Which methods would I need to override in order to get the values to be set in my bounded Children object regardless of the immediate flag?
And of course, if anybody has any other design suggestions I'm open to them!
Thanks in advance!
/Kris

Answer 1

nboudani , let me answer your question first. The page does have a Submit button. It also has "Add Child" and "Remove Child", and some others as well. The Submit button has immediate="false". I also need form validation for interdependent form fileds (e.g. either Passport number or social security number are required), so I'm using the "hidden input field at the bottom of the form trick". This all works well enough.
OK, I got partway there. jaguar2010's mention of valueChangeListener made me investigate that further. So what I did was twofold. Set the immediate attribute to true for the inputText elements in question (for the Children data) as well as for the commandButton (as before). Also, add a valueChangeListener for each of the Children which simply calls updateModel.
So, view code:
<h:inputText id="cName"
                       valueChangeListener="#{testBean.procCNameValueChanged}"
                       value="#{child.name}"
                       required="true"
                       immediate="true"/>
<h:inputText id="cSS"
                       valueChangeListener="#{testBean.processCSSValueChanged}"
                       value="#{child.ss}"
                       validator="#{testBean.validateCSS}"
                       immediate="true"/>
<h:commandButton action="#{testBean.addChild}" immediate="true" value="Add Child"/>
...bean code:
public void procCNameValueChanged(ValueChangeEvent event) {
    HtmlInputText sender = (HtmlInputText) event.getComponent();
    sender.updateModel(FacesContext.getCurrentInstance());
}So, that does take care of the problem with the model not updating. However, there are a bunch of other problems still left to be resolved. For instance, as you'll notice, there is a validator attached to one of the inputs. If this validation fails, the invalid text is not put back in the input field. I can't temember now, but I think that is because the valueChangeListener is not called in that case, so the model is not updated. Sigh...
Another problem is that for each row in the data model's table, there is a "Remove" button (not shown in above code) to enable the user to remove an entry from the list of children. Well, because JSF process events in the order of their appearance in the view code, an exeption is thrown if the removed row is not the last one, and the last row has not been "saved" yet. That is, the valueChangeListener has not been called on the last row. What happens is that first the action method for the remove button is called, then the valueChangeListener for the last row is called. But by the time the valueChangeListener event is fired, the last row has chaned its index (because the remove action method was called first) and apparently this fact has escaped JSF so it throws an exception (property not found or something).
I'm starting to wonder if JSF is the wrong technology for complex forms. Just seems to want to do too much for me, assuming I have a simple form.