How to validate when navigating on next page in a Train

Question

Dear All,
Use Case:
I have pages arranged in a Train.
Supposed in 1 page, I have this code.
<af:selectBooleanRadio text="Enter new transaction details"
   label="" id="sbr2"
   autoSubmit="true"
   value="#{pageFlowScope.myBean.option}"/>
<af:panelFormLayout id="option" labelAlignment="start"
     rendered="#{pageFlowScope.myBean.option}">
     <af:inputText label="Transaction Date" id="it2"/>
     <af:inputText label="Transaction Option" id="it3"/>
     <af:inputText label="Confirmation Message" id="it7"/>
     <f:facet name="footer"/>
</af:panelFormLayout>If the user selected the boolean radio, I will display the panelformlayout thru PPR.
Now, if the panelformlayout is displayed, user should at least enter one data on at least one
of the inputText. If not, a message is displayed when user navigates to the next page on the
train.
How to do this?
I cannot put a required property on all the input text because not all are required and only at least one input text should be filled up.
I wanted to fire up when user navigates the train button Previous or Next button.
JDEV 11G PS3
Thanks

Answer 1

one solution is to build your own Next button in the train and check the condition before you navigate to the next train stop. to navigate to the next train stop in the train check check [url http://www.oracle.com/technetwork/developer-tools/adf/learnmore/82-programmatically-navigate-trains-396873.pdf]     How-to programmatically navigate ADF train models
another solution is to set the required property for your input texts as
<af:inputText label="Transaction Date" id="it2"/>
     <af:inputText label="Transaction Option" id="it1" required="boolean radio is selected and it2 eq null and it3 eq null ...... and it7 is null"/>
     <af:inputText label="Transaction Option" id="it2" required="boolean radio is selected and it1 eq null and it3 eq null ...... and it7 is null"/>
        <af:inputText label="Transaction Option" id="it3" required="boolean radio is selected and it1 eq null and it2 eq null ...... and it7 is null"/>
     <af:inputText label="Confirmation Message" id="it7" required"boolean radio is selected and it1 eq null and ...... it6 eq null"/>