如何将素面自动完成对象放入后备bean

Question

i need to send the the primeface auto-complete object in to backing bean while user clicks on "Add" button. in this case the primeface auto complete function works properly. but while sending the selected object in to backing bean it always gives me a null pointer

this is my page

<h:form id="orderForm" >

                <p:outputLabel value="Item : " for="acItem" />
                <p:autoComplete id="acItem" value="#{orderController.item}" completeMethod="#{orderController.completeItem}"
                                var="item" itemLabel="#{item.itemDescription}" itemValue="#{item}" converter="itemConverter" forceSelection="true" />

                <p:outputLabel value="Qty : " for="itemQty" />
                <p:inputText id="itemQty" value="#{orderController.quantity}"/>

                <p:commandButton id="add" value="AddItem" update="dataTable" actionListener="#{orderController.addItemsToDataTable(item)}"/>


                    <p:dataTable id="dataTable" value="#{orderController.orderdItems}" var="item" paginator="true" rows="10">
                        <p:column>
                            <f:facet name="header">
                                <h:outputText value="Item ID"/>
                            </f:facet>
                            <h:outputText value="#{item.itemId}"/>
                        </p:column>
                        <p:column>
                            <f:facet name="header">
                                <h:outputText value="Item Code"/>
                            </f:facet>
                            <h:outputText value="#{item.itemCode}"/>

                        </p:column>
                        <p:column>
                            <f:facet name="header">
                                <h:outputText value="Customer Name"/>
                            </f:facet>
                            <h:outputText value="#{item.itemDescription}"/>

                        </p:column>                            
                    </p:dataTable>

                    <h:commandButton id="save" value="Save"
                                     action="#{orderController.createOrder}" />

                    <h:messages />

            </h:form>

and this is my baking bean

    import java.util.ArrayList;
    import java.util.List;

    import javax.faces.bean.ManagedBean;
    import javax.faces.bean.ManagedProperty;
    import javax.faces.bean.RequestScoped;

    import org.springframework.stereotype.Component;

    import com.kpowd.model.Item;
    import com.kpowd.model.Order;
    import com.kpowd.model.OrderItem;
    import com.kpowd.service.ItemService;
    import com.kpowd.service.OrderService;
    import com.kpowd.service.UserService;
    import java.io.Serializable;
    import javax.annotation.PostConstruct;
    import javax.faces.bean.ViewScoped;
    import javax.faces.event.ActionEvent;

    @Component
    @ManagedBean
    @ViewScoped
    public class OrderController implements Serializable{

        @ManagedProperty(value = "#{orderService}")
        public OrderService orderService;
        @ManagedProperty(value = "#{itemService}")
        public ItemService itemService;
        public Item item;
        public List<Item> allItems;
    //    public List<Item> acFilterdItem;
        public int quantity;
        public List<Item> orderdItems;

        @PostConstruct
        public void Init(){
            allItems = itemService.getAllItems();
            System.out.println("item array size : "+allItems.size());
            orderdItems = new ArrayList<Item>();
        }

        public List<Item> completeItem(String query) {
            List<Item> acFilterdItem = new ArrayList<Item>();

            for (int i = 0; i < allItems.size(); i++) {
                  if(allItems.get(i).getItemCode().toLowerCase().startsWith(query)){
                  acFilterdItem.add(allItems.get(i));
                  }
            }

            return acFilterdItem;
        }

        public void addItemsToDataTable(Item item){
// this is the object that gets null each time
            System.out.println("inside addItemsToDataTable");
            System.out.println("Print : "+item.toString());
    //        System.out.println("Item : "+item.getItemCode()+ " : " +item.getItemDescription());
            orderdItems.add(item);
    //        return "";
        }

    }

please help me.....

Answer 1

I think it's due because the commandButton attribute :

actionListener="#{orderController.addItemsToDataTable(item)}"

does not know the item parameter you're trying to pass with. While the class attribute item is supposed having getter/setter, so just switch that method signature to this one :

actionListener="#{orderController.addItemsToDataTable(orderController.item)}"

Or even, you can omit it, and keep it like :

actionListener="#{orderController.addItemsToDataTable}"

plus in the managedBean: public void addItemsToDataTable( ){ ... } .