How to transfer data retrieved from a bean, into requestScope

Question

I have a jsf page called viewCustomer.jsp, which is backed by a controller/mbean with a name viewCustomerController.
This page is always called via a request which carries the customer accountID in its request attributes. Hence in order to load the customer details i am using a f:view beforephase call which acts before the render phase. This retrieves a number of beans from of different types. For example, each customer can have an address.
each addressbean has an ID field which is the primary key to the addresses. If i want to delete the address, i need to send this primary key via a requestAttribute to a controller which will delete it.
hence to delete the address i have a form such as:-
<h:form>
<h:inputHidden value="#{viewCustomerController.customerAddressBean.id}" />
<h:commandButton value="Delete Address" action="#{viewCustomerController.deleteCustomerAddress}" />
</h:form>
The problem with this, is that because the addressbean is only added before the render phase, on presssing the delete address button, i get a null exception, because customerAddressBean doesnt exist yet.
What i want to do, is that upon pressing the delete address button, the id value should be immediately sent to a requestAttribute called 'addressId', and not back to the backing bean.
i. e. (if jsf had an assignment operator) it would be something like
<h:form>
<h:inputHidden value="requestScope.addressID = #{viewCustomerController.customerAddressBean.id}" />
<h:commandButton value="Delete Address" action="#{viewCustomerController.deleteCustomerAddress}" />
</h:form>
basically, the data should be read from the backing bean, but it shouldnt be written back to the backing bean.
now i realize that if i allow my database to repopulate the backing bean earlier, the customerAddressBean will be populated, and then the first listing would work. But that would require a second set of trips to the database with no meaning but to repopulate the backing bean which seems like quite a waste.
In the case of the address, i could populate the propertly with a dummy addressbean, but this would not work in the case of properties which are lists of beans.
So in summation. How do i transfer data that has been read from a property of a backing bean, into a request attribute on a commandbutton click, without putting the data back into the property of the backing bean.

Answer 1

Hello Anu,
There are different hardware options that you have here. The basic things that you need to keep in mind is that the PDA that you purchase runs on Pocket PC and has either a CompactFlash or a PCMCIA slot in it. The driver that you would be using for your LabVIEW PDA application would NI-DAQmx Base Ver 2.0.1. You can refer to its readme for more information on the supported hardware. Also you can check at this page for more information on the supported devices. About your original question, using LabVIEW PDA you can create a text file for storing data and separate the data points with a comma. So that this way you would be able to open the file in Excel if you wanted to. All the file I/O related VIs can be found in the function palette at Programming >> File I/O.
Regards,
Chetan K.
Application Engineer
National Instruments