changing values of selectOneMenu in JSF - jsf

Question

I am new to JSF and i am stuck at one place. I have one dropdown list which contains two items.
Bank
Cash
Now, if I select bank the other dropdown should populate items related to bank and if I select cash, cash items should be shown in 2nd dropdown.
How to do it in JSF? Where I have to make changes?
Any help will be highly appreciated.Thanks

Answer 1

Well you can use primefaces to improve jsf development
<p:selectOneMenu id="cboCountries" value="#{beanCountries.ValueSelected}" effect="fade">
<f:selectItem itemLabel="Select Country" itemValue="-1" /> //a default value
<f:selectItems value="#{beanCountries.listOfCountries}" var="countries" itemLabel="#{countries.name}" itemValue="#{countries.id}"/>
<p:ajax event="change" update="cboCities" listener="beanCountries.listCities()"/> //notice "update" refresh an especific DOM Element of an especific ID
</p:selectOneMenu>
<p:selectOneMenu id="cboCities" value="#{beanCities.ValueSelected}" effect="fade">
<f:selectItem itemLabel="Select City" itemValue="-1" /> //a default value
<f:selectItems value="#{beanCities.listOfCities}" var="cities" itemLabel="#{cities.name}" itemValue="#{cities.id}"/> //this is when you want to put elements from DB or from an Array
</p:selectOneMenu>
" is a special mark from primefaces, the event = "change" will invoke the you select an element from the first "ComboBox" then the property update will refresh the second comboBox, and the property "listener" will do the logical action of what you want to do, in this case the method "listCities()" will fill "listOfCities" with values from DB o Arrays.
So in jsf without primefaces will be like this:
<h:form>
<h:selectOneMenu value="#{beanCountries.ValueSelected}">
<f:selectItem itemLabel="Select Country" itemValue="-1" /> //a default value
<f:selectItems value="#{beanCountries.listOfCountries}" var="countries" itemLabel="#{countries.name}" itemValue="#{countries.id}"/>
</h:selectOneMenu>
<h:selectOneMenu id="cboCities" value="#{beanCities.ValueSelected}">
<f:selectItem itemLabel="Select City" itemValue="-1" /> //a default value
<f:selectItems value="#{beanCities.listOfCities}" var="cities" itemLabel="#{cities.name}" itemValue="#{cities.id}"/> //this is when you want to put elements from DB or from an Array
</h:selectOneMenu>
<h:commandButton value="Submit" action="beanCountries.listCities()"/>
</h:form>
this way is with a button (in jsf) and the action property will execute a java Method and then refresh the page. also this could be made by "ValueChangeListener" property of the selectOneMenu component