SelectOneMenu depends to other selectOneMenu - Jsf - jsf

Question

I have a Webapp with the Technologies: Wildfly, JSF, Primefaces
I have to select One Menus. The first Select One Menu loads all Warehouses and the second Select One Menu loads all Products which depends to the selected Warehouse.
I want to implemente the posibility, that i don't have necessarily choose a warehouse. I want to have the possibility that i dont select a warehouse, and logically if i dont choose a warehouse, the product Select one menu has to be disabled.
If i submit the form without a warehouse, it should be written in the database null for warehouse and also null for product.
My first attempt was to do the following entry in the select one menu of warehouse.
<f:selectItem itemLabel="---" itemValue="#{null}" value="#{null}"/>
Now, i don't know how to set the value of the warehouse select one menu to null, if i haven't choose a warehouse.
value="#{warehouseDataActions.actualWarehouse}" --> how to set to null
The second Problem is, that in the Ajax of the first select one menu i have to add the Attribute immediate = true. This Attribute is only neccassary for me if i add the following line. I don't know why ?
<f:selectItem itemLabel="---" itemValue="#{null}" value="#{null}"/>
So i have three questions:
1-How to set the actualWarehouse and .actualWriteservice.warehouseProduct to null ?
How to disable the product select one menu if i have already doesn not choose a warehouse (---) above ?
Why does my Ajax request in the warehouse select one menu does not function, if i add the item
<p:selectOneMenu style="width:151px"
value="#{warehouseDataActions.actualWarehouse}">
<f:converter converterId="ccWarehouseConverter" />
<f:selectItem itemLabel="---" itemValue="#{null}" value="#{null}"/>
<f:selectItems
value="#{warehouseDataActions.allWarehousesForProject}"
var="warehouse"
itemLabel="#{warehouse.warehouseName}"
itemValue="#{warehouse}" />
<p:ajax listener="#{warehouseProductDataActions.warehouseProductsForWarehouse}"
update="products" />
<p:panelGrid>
<p:outputLabel for="products">#{texts['writeservice.product']}</p:outputLabel>
<p:selectOneMenu id="products" style="width:151px"
value="#{writeserviceDataActions.actualWriteservice.warehouseProduct}">
<f:converter converterId="ccWarehouseProductConverter" />
<f:selectItems
value="#{warehouseProductDataActions.warehouseProductsResult}"
var="warehouseProduct" itemLabel="#{warehouseProduct.product.productName}"
itemValue="#{warehouseProduct}" />
</p:selectOneMenu>
</p:panelGrid>

Answer 1

You need to handle the --- case in your converter
(ccWarehouseConverter).
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
if (value == null || value.length() == 0 || value.equalsIgnoreCase("---")) {
return null;
}
return databaseService.getWarehouseByName(value);
}
To disable the selectOne
<p:panelGrid>
<p:outputLabel for="products">#{texts['writeservice.product']}</p:outputLabel>
<p:selectOneMenu id="products" style="width:151px" disabled="#{empty warehouseDataActions.actualWarehouse}"
value="#{writeserviceDataActions.actualWriteservice.warehouseProduct}">
<f:converter converterId="ccWarehouseProductConverter" />
<f:selectItems
value="#{warehouseProductDataActions.warehouseProductsResult}"
var="warehouseProduct" itemLabel="#{warehouseProduct.product.productName}"
itemValue="#{warehouseProduct}" />
</p:selectOneMenu>
</p:panelGrid>
In order to have your ajax update working, you must encapsulate both warehouse and products in a mother panel, and you update the mother:
<h:panelGroup id="motherPanel" layout="block">
<p:selectOneMenu style="width:151px" value="#{warehouseDataActions.actualWarehouse}">
<f:converter converterId="ccWarehouseConverter" />
<f:selectItem itemLabel="---" itemValue="#{null}" value="#{null}"/>
<f:selectItems
value="#{warehouseDataActions.allWarehousesForProject}"
var="warehouse"
itemLabel="#{warehouse.warehouseName}"
itemValue="#{warehouse}" />
<p:ajax listener="#{warehouseProductDataActions.warehouseProductsForWarehouse}"
update="motherPanel" />
</p:selectOneMenu>
<p:panelGrid>
<p:outputLabel for="products">#{texts['writeservice.product']}</p:outputLabel>
<p:selectOneMenu id="products" style="width:151px" disabled="#{empty warehouseDataActions.actualWarehouse}"
value="#{writeserviceDataActions.actualWriteservice.warehouseProduct}">
<f:converter converterId="ccWarehouseProductConverter" />
<f:selectItems
value="#{warehouseProductDataActions.warehouseProductsResult}"
var="warehouseProduct" itemLabel="#{warehouseProduct.product.productName}"
itemValue="#{warehouseProduct}" />
</p:selectOneMenu>
</p:panelGrid>
</h:panelGroup>