ZK with EJB3.1 running on Glassfish (Part 2)

In part 1 we connected a web application to a database using an EJB for reading access, deployed on a Glassfish Server. In part 2 we do some modifications to create a true CRUD application by adding add, delete and update.

Pre-Requirements:

• Netbeans 6.7 or later
• Installed ZK plugin (link)
• Glassfish V3 or later
• Netbeans Project from Part 1 (link)

Tutorial:

1. EJB modifications
   are not required because for the basic CRUD functions we will use the provide abstract facade.

   package ejb;
   
   import java.util.List;
   import javax.persistence.EntityManager;
   
   public abstract class AbstractFacade<T> {
    private Class<T> entityClass;
   
    public AbstractFacade(Class<T> entityClass) {
    this.entityClass = entityClass;
    }
   
    protected abstract EntityManager getEntityManager();
   
    public void create(T entity) {
    getEntityManager().persist(entity);
    }
   
    public void edit(T entity) {
    getEntityManager().merge(entity);
    }
   
    public void remove(T entity) {
    getEntityManager().remove(getEntityManager().merge(entity));
    }
   
    public T find(Object id) {
    return getEntityManager().find(entityClass, id);
    }
   
    public List<T> findAll() {
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    cq.select(cq.from(entityClass));
    return getEntityManager().createQuery(cq).getResultList();
    }
   
    public List<T> findRange(int[] range) {
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    cq.select(cq.from(entityClass));
    javax.persistence.Query q = getEntityManager().createQuery(cq);
    q.setMaxResults(range[1] - range[0]);
    q.setFirstResult(range[0]);
    return q.getResultList();
    }
   
    public int count() {
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    javax.persistence.criteria.Root<T> rt = cq.from(entityClass);
    cq.select(getEntityManager().getCriteriaBuilder().count(rt));
    javax.persistence.Query q = getEntityManager().createQuery(cq);
    return ((Long) q.getSingleResult()).intValue();
    }
   
   }
   
   

2. Modification of the zul file
   We add a button for delete and a grid with the 3 table columns, plus update and create buttons.

   <?xml version="1.0" encoding="UTF-8"?>
   
   <zk xmlns="http://www.zkoss.org/2005/zul">
    <?init?>
    <window id="list" apply="controller.indexController" title="Customer List">
    <listbox id="lst" width="100%" >
    <listhead sizable="true">
    <listheader id="col1" label="Company"/>
    <listheader id="col2" label="First Name" />
    <listheader id="col3" label="Last Name" />
    </listhead>
    </listbox>
   
    <button id="btnDelete" label="Delete record"/>
    <separator bar="true"/>
   
    <grid width="40%">
    <columns>
    <column label=""/>
    <column label=""/>
    </columns>
    <rows>
    <row>
    <label value="Company:" />
    <textbox id="txtCompany" value=""/>
    </row>
    <row>
    <label value="First:" />
    <textbox id="txtFirst" value=""/>
    </row>
    <row>
    <label value="Last:" />
    <textbox id="txtLast" value=""/>
    </row>
    </rows>
    </grid>
   
    <button id="btnUpdate" label="Update record"/>
    <button id="btnAdd" label="Add record"/>
    </window>
   </zk>
   

3. Modification to the controller class
   We need to add variables for the additional components, create a separate instance of the model to update the listbox without re-reading the data from the DB when changes are applied.

   package controller;
   
   import ejb.customerZK;
   import ejb.customerFacade;
   import java.util.ArrayList;
   import java.util.List;
   import javax.naming.Context;
   import javax.naming.InitialContext;
   import org.zkoss.zk.ui.Component;
   import org.zkoss.zk.ui.event.Event;
   import org.zkoss.zk.ui.util.GenericForwardComposer;
   import org.zkoss.zul.Button;
   import org.zkoss.zul.ListModelList;
   import org.zkoss.zul.Listbox;
   import org.zkoss.zul.Listcell;
   import org.zkoss.zul.Listitem;
   import org.zkoss.zul.ListitemRenderer;
   import org.zkoss.zul.Textbox;
   
   public class indexController extends GenericForwardComposer {
   
    Context context;
    customerFacade facade;
    List<customerZK> customer = null;
    ListModelList model;
    private Listbox lst;
    private Textbox txtLast;
    private Textbox txtFirst;
    private Textbox txtCompany;
   
    @Override
    public void doAfterCompose(Component comp) throws Exception {
    super.doAfterCompose(comp);
   
    context = new InitialContext();
   
    try {
    facade = (customerFacade) context.lookup("java:global/ZK_EJB_WEB/customerFacade");
   
    // Read all records and store it in a arraylist
    customer = new ArrayList();
    customer.addAll(facade.findAll());
   
    // Set listmodel for the ZK list component
    model = new ListModelList(customer);
    lst.setModel(model);
   
    // Custom renderer
    ListitemRenderer listitem = new ListitemRenderer() {
   
    @Override
    public void render(Listitem item, Object data) throws Exception {
    item.setValue(data);
    item.appendChild(new Listcell(((customerZK) data).getCompanyName()));
    item.appendChild(new Listcell(((customerZK) data).getFirstName()));
    item.appendChild(new Listcell(((customerZK) data).getLastName()));
    }
    };
    lst.setItemRenderer(listitem);
   
   } catch (Exception e) {
    System.out.println(e.getMessage());
    }
    }
   
    public void onSelect$lst(Event evt) throws InterruptedException {
    // read values from selected record
    txtLast.setValue(((customerZK) lst.getSelectedItem().getValue()).getLastName());
    txtFirst.setValue(((customerZK) lst.getSelectedItem().getValue()).getFirstName());
    txtCompany.setValue(((customerZK) lst.getSelectedItem().getValue()).getCompanyName());
    }
   
    public void onClick$btnDelete(Event evt) throws InterruptedException {
    System.out.println("Deleting ID: " + ((customerZK) lst.getSelectedItem().getValue()).getId());
    // persist
    facade.remove((customerZK) lst.getSelectedItem().getValue());
    // update listmodel
    model.remove((customerZK) lst.getSelectedItem().getValue());
    }
   
    public void onClick$btnUpdate(Event evt) throws InterruptedException {
    customerZK modCustomer = new customerZK();
   
    // read values from textbox
    modCustomer.setId(((customerZK) lst.getSelectedItem().getValue()).getId());
    modCustomer.setCompanyName(txtCompany.getValue());
    modCustomer.setFirstName(txtFirst.getValue());
    modCustomer.setLastName(txtLast.getValue());
   
    // persist
    facade.edit(modCustomer);
    // update listmodel
    model.set(model.indexOf((customerZK) lst.getSelectedItem().getValue()) , modCustomer);
   
    }
   
    public void onClick$btnAdd(Event evt) throws InterruptedException {
   
    customerZK modCustomer = new customerZK();
   
    modCustomer.setCompanyName(txtCompany.getValue());
    modCustomer.setFirstName(txtFirst.getValue());
    modCustomer.setLastName(txtLast.getValue());
   
    // persist
    facade.create(modCustomer);
    // update listmodel
    model.add(modCustomer);
   
    }
   }
   

4. Run the application
   

   Running ZK application

Remarks:

• There are smarter (?) ways to bind the textbox to an entity, but for the sake of simplicity I used this hands-on approach.
• Complete Netbeans projects: http://sourceforge.net/projects/coffeeshop/files (ZK_EJB_WEB_0.2.zip and ZK_EJB_0.1.zip)

About these ads