EJB CMP or Hibernate?????/

strikepollar · **Joined:** Thu Apr 01, 2004 6:28 pm **Posts:** 15

Which one is best suited for large applications
I'm kind resistent to the idea that session beans using hibernate can run faster or more stable than just plain cmp, but maybe I'm biased
Anyone

micho2001 · **Posted:** Tue Apr 06, 2004 12:30 am

I dont really have any benchmarks to speak off comparing CMP to Hibernate.

One bad thing about CMP is the N+1 Db hits problem when you use finder methods to load a collection , a potential performance drag! In big apps you will normally find the DB to be your bottleneck, mainly cause its the hardest place to run in parallel.

One good thing about CMP is that you can have the App server run your app distributed.

IMHO Hibernate is much more flexible when it comes to handle fine grained models.

What do you mean by large? In storage? Transaction intensive? Is it web based? This are thing you have to consider

roofimon · **Posted:** Tue Apr 06, 2004 12:48 am

Hibernate for sure.

Currently, we are using

Servlet
| ----call---->SessionBean
|----call------>DAO
|----call----->Hibernate

It's really cool....................

igod · **Joined:** Tue Apr 06, 2004 9:15 am **Posts:** 4

Hi,

I'm begining to learn hibernate.
I like your solution. Could you give an example that I could see it in action.
Example: a zip with Servlet, SessionBean, DAO and Hibernate files of one simple code like simple reading and writing contacts to DB.

Thanks,
Paulo

roofimon wrote:

Hibernate for sure.

Currently, we are using

Servlet
| ----call---->SessionBean
|----call------>DAO
|----call----->Hibernate

It's really cool....................

roofimon · **Posted:** Wed Apr 07, 2004 12:30 am

OK, This is the beginning an Interface class

Code:

package com.netplus.workstation.pprincess;

import java.sql.Blob;

public interface Limousine {

   Long getLimousineId();
   void setLimousineId(Long limId);

   String getLimousineType();
   void setLimousineType(String limType);
   
   String getDescription();
   void setDescription(String description);
   
   Double getRate();
   void setRate(Double rate);
   
   Blob getPicture();
       void setPicture(Blob pic);
   
   String getFileName();
   void setFileName(String fileName);
   
   int getFileSize();
   void setFileSize(int fileSize);
}

And here is My Real Hibernate Obj that implement above Interface

Code:

package com.netplus.workstation.pprincess.hibernate.entity;

import com.netplus.workstation.pprincess.Limousine;
import java.sql.Blob;
import java.io.Serializable;
/**
 * @castor.class
 * @hibernate.class table="LIMOUSINE"
 */
public class HibernateLimousine implements Limousine , Serializable {

   private Long limousineId;
   private String limousineType;
   private String description;
   private Double rate;
   private Blob picture;
   private String fileName;
   private int fileSize;

   /**
    * @castor.field    
    *      type = "java.lang.Long"
    * @castor.field-xml
    *      name = "limousineId"
    *      node = "attribute"
    * @hibernate.id
    *  generator-class="assigned"
    *  unsaved-value="0"
    */
   public Long getLimousineId(){
      return limousineId;
   }
   public void setLimousineId(Long limousineId){
      this.limousineId = limousineId;
   }
   
   
   /**
    * @castor.field    
    *      type = "java.lang.String"
    * @castor.field-xml
    *      name = "limousineType"
    *      node = "element"
    * @hibernate.property
    */
   public String getLimousineType(){
      return limousineType;
   }
   public void setLimousineType(String limousineType){
      this.limousineType = limousineType;
   }
   
   /**
    * @castor.field    
    *      type = "java.lang.String"
    * @castor.field-xml
    *      name = "description"
    *      node = "element"
    * @hibernate.property
    */
   public String getDescription(){
      return description;
   }
   public void setDescription(String description){
      this.description = description;
   }
   
   /**
    * @castor.field    
    *      type = "java.lang.Double"
    * @castor.field-xml
    *      name = "rate"
    *      node = "element"
    * @hibernate.property
    */
   public Double getRate(){
      return rate;
   }
   public void setRate(Double rate){
      this.rate = rate;
   }
   
   /**
    * @castor.field    
    *      type = "java.sql.Blob"
    * @castor.field-xml
    *      name = "picture"
    *      node = "element"
    * @hibernate.property
    */
   public Blob getPicture(){
      return picture;
   }
       public void setPicture(Blob picture){
      this.picture = picture;
   }
   
   /**
    * @castor.field    
    *      type = "java.lang.String"
    * @castor.field-xml
    *      name = "fileName"
    *      node = "element"
    * @hibernate.property
    */
   public String getFileName(){
      return fileName;
   }
   public void setFileName(String fileName){
      this.fileName = fileName;
   }
   
   /**
    * @castor.field    
    *      type = "integer"
    * @castor.field-xml
    *      name = "fileSize"
    *      node = "element"
    * @hibernate.property
    */
   public int getFileSize(){
      return fileSize;
   }
   public void setFileSize(int fileSize){
      this.fileSize = fileSize;
   }
}

roofimon · **Posted:** Wed Apr 07, 2004 12:34 am

Again this is my Interface FOR DAO

Code:

package com.netplus.workstation.pprincess.hibernate.dao;

import java.util.List;
import com.netplus.workstation.pprincess.Limousine;
import net.sf.hibernate.HibernateException;

public interface HibernateLimousineDAO {
       public Limousine create(String limType,String description,Double rate,byte[] pic,String fileName,int fileSize) throws Exception;
       public List findByAll() throws Exception;
       public Limousine findByPrimaryKey(long limId) throws Exception;
       public void init() throws HibernateException;
       public void remove(long limId) throws Exception;
       public void update(Limousine limousine) throws Exception;
}

And this is my Real DAO

Code:

package com.netplus.workstation.pprincess.hibernate.impl;

import java.util.List;
import java.io.Serializable;
import javax.ejb.EJBException;
import javax.naming.Context;
import javax.naming.NamingException;
import javax.naming.InitialContext;
import net.sf.hibernate.SessionFactory;
import net.sf.hibernate.Session;
import net.sf.hibernate.Hibernate;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Transaction;
import net.sf.hibernate.Query;
import com.netplus.workstation.pprincess.Limousine;
import com.netplus.workstation.pprincess.hibernate.dao.HibernateLimousineDAO;
import com.netplus.workstation.pprincess.hibernate.entity.HibernateLimousine;


public class HibernateLimousineDAOImpl implements HibernateLimousineDAO , Serializable {
   
    private Session hbSession;
    private SessionFactory factory;
 
    
    public HibernateLimousineDAOImpl() {
    }
    
    
    public Limousine create(String limType, String description, Double rate, byte[] pic, String fileName, int fileSize) throws Exception{
        try{
            System.out.println("Create Limousine.");
            hbSession = factory.openSession();
            Transaction tx = hbSession.beginTransaction();
       HibernateLimousine hLimousine = new HibernateLimousine();
       hLimousine.setLimousineType(limType);
       hLimousine.setDescription(description);
       hLimousine.setRate(rate);
       hLimousine.setPicture(Hibernate.createBlob(pic));
       hLimousine.setFileName(fileName);
       hLimousine.setFileSize(fileSize);
       long id;
            try{
          id = ((Long)(hbSession.iterate("select max(limousine.limousineId) from com.netplus.workstation.pprincess.hibernate.entity.HibernateLimousine limousine").next())).longValue()+1;
       } catch(Exception ex){
          id = 1;
       }
            Long genId = new Long(id);
            hbSession.save(hLimousine, genId);
            tx.commit();
            return (Limousine)hbSession.load(HibernateLimousine.class, genId);
        }catch(HibernateException error){
            throw new Exception("Error saving object: "+ error.toString());
        }catch(Exception e){
            e.printStackTrace();
            return null;
        }finally{
            hbSession.close();
        }
    }
    
    
    public List findByAll() throws Exception {
   try{
            System.out.println("Find Limousine All.");
            hbSession = factory.openSession();
            Transaction tx = hbSession.beginTransaction();
       Query query = hbSession.createQuery("from com.netplus.workstation.pprincess.hibernate.entity.HibernateLimousine");
       List list = query.list();
            System.out.println("Get Limousine size? "+list.size());
       return list;
        }catch(HibernateException error){
            throw new Exception("Error FindByAll = "+error.toString());
        }catch(Exception error){
            error.printStackTrace();
            return null; 
        }finally{
            hbSession.close();
        }
    }
    
    public Limousine findByPrimaryKey(long limId) throws Exception{
        try{
            System.out.println("Find By Limousine Id.");
            hbSession = factory.openSession();
            Transaction tx = hbSession.beginTransaction();
            HibernateLimousine hLimousine = (HibernateLimousine)hbSession.load(HibernateLimousine.class, new Long(limId));
       return (Limousine)hLimousine;
        }catch(HibernateException error){
            throw new Exception("Error find by limousine id = "+ limId +" . "+error.toString());
        }catch(Exception error){
            error.printStackTrace();
            return null; 
        }finally{
            hbSession.close();
        }
    }
    
    public void init() throws HibernateException {
        try {
            System.out.println("Init DAO");
            Context ctx = new InitialContext();
           try {
                    factory = (SessionFactory) ctx.lookup("java:/PPrincessHibernateFactory");
                } catch (NamingException e) {
                    throw new EJBException("Error looking up dataSource: " + e.toString());
                }
   } catch (NamingException e) {
      throw new EJBException("Error initializing context:" + e.toString());
   }
    }
    
    
    public void remove(long limId) throws HibernateException {
        try{
            System.out.println("Remove Limousine.");
            hbSession = factory.openSession();
            Transaction tx = hbSession.beginTransaction();
            HibernateLimousine hLimousine = (HibernateLimousine)hbSession.load(HibernateLimousine.class, new Long(limId));
            hbSession.delete(hLimousine);
            tx.commit();
        }catch(HibernateException error){
            
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            hbSession.close();
        }
    }
    
    public void update(Limousine limousine) throws Exception{
        try{
            System.out.println("Update Limousine.");
            hbSession = factory.openSession();
            Transaction tx = hbSession.beginTransaction();
            hbSession.saveOrUpdate(limousine);
            tx.commit();
        }catch(HibernateException error){
            throw new Exception("Error updating object: "+ error.toString());
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            hbSession.close();
        }
    }

}

[/code]

roofimon · **Posted:** Wed Apr 07, 2004 12:37 am

Here is my Session Bean

Code:

package com.netplus.workstation.pprincess.ejb;

import com.netplus.workstation.pprincess.hibernate.dao.HibernateLimousineDAO;
import com.netplus.workstation.pprincess.hibernate.entity.HibernateLimousine;
import com.netplus.workstation.pprincess.Limousine;
import net.sf.hibernate.HibernateException;
import java.util.List;
/**
 * 
 * @ejb.bean 
 *    name="Limousine" 
 *    type="Stateful" 
 *    view-type="remote"
 *    jndi-name="hibernate/com.netplus.workstation.pprincess.ejb.Limousine"
 * 
 * @ejb.home
 *    remote-class="com.netplus.workstation.pprincess.ejb.LimousineHome"
 *    extends = "javax.ejb.EJBHome"
 * 
 * @ejb.interface
 *    remote-class="com.netplus.workstation.pprincess.ejb.LimousineRemote" 
 *    extends="javax.ejb.EJBObject"
 * 
 * @ejb.env-entry 
 *    name="limousineDao" 
 *    type="java.lang.String"
 *    value="com.netplus.workstation.pprincess.hibernate.impl.HibernateLimousineDAOImpl"
 *
 * @ejb.util
 *   generate = "physical"
 *
 * @jboss.web-xml
 *   ref-name = "Limousine"
 *   jndi-name = "hibernate/com.netplus.workstation.pprincess.ejb.Limousine"
 *
 * @web.ejb-ref
 *   name = "Limousine"
 *   type = "Session"
 *   home = "com.netplus.workstation.pprincess.ejb.LimousineHome"
 *   remote = "com.netplus.workstation.pprincess.ejb.LimousineRemote"
 *
 */
public class LimousineFacadeEJB implements javax.ejb.SessionBean {

   private HibernateLimousineDAO limousineDao;

   public LimousineFacadeEJB() {
   }

   public void ejbCreate() {

   }
   public void ejbActivate() {
   }

   public void ejbPassivate() {
   }

   public void ejbRemove() {
   }

   public void setSessionContext(javax.ejb.SessionContext sessionContext) {
   }

   /**
   *@ejb.interface-method
   **/
   public Limousine createLimousine(String limType, String description, Double rate, byte[] pic, String fileName, int fileSize){
      try{
         return this.getDAO().create(limType, description, rate, pic, fileName, fileSize);
      }catch(Exception error){
         error.printStackTrace();
         return null;
      }
   }

   /**
    * @ejb.interface-method
    */
   public List getAllLimousines() {
      try {
         return this.getDAO().findByAll();
      } catch (Exception error) {
         error.printStackTrace();
         return null;
      }
   }
   
   /**
    * @ejb.interface-method
    */
   public Limousine getLimousineInstance(){
      return (Limousine) (new HibernateLimousine());
   }
   
   /**
    * @ejb.interface-method
    */
   public Limousine findByPrimaryKey(long limId) {
      try {
         return (Limousine)this.getDAO().findByPrimaryKey(limId);
      } catch (Exception error) {
         error.printStackTrace();
         return null;
      }
   }


   /**
    * @ejb.interface-method
    */
   public void removeLimousine(long limId) {
      try {
         this.getDAO().remove(limId);
      } catch (Exception error) {
         error.printStackTrace();
      }
   }

   /**
    * @ejb.interface-method
    */
   public void updateLimousine(Limousine limousine) {
      try {
         this.getDAO().update(limousine);
      } catch (Exception error) {
         error.printStackTrace();
      }
   }

   public HibernateLimousineDAO getDAO() throws HibernateException {
      if (limousineDao != null) {
         return limousineDao;
      } else {

         try {
            javax.naming.InitialContext ctx = new javax.naming.InitialContext();
            Object ref = ctx.lookup("java:comp/env/limousineDao");
            String daoStr = (String) javax.rmi.PortableRemoteObject.narrow(ref, String.class);
            limousineDao = (HibernateLimousineDAO) Class.forName(daoStr).newInstance();
         } catch (javax.naming.NamingException e) {
            throw new IllegalStateException(
               "DAO not defined in JNDI 'java:comp/env/limousineDao': " + e.getLocalizedMessage());
         } catch (Exception e) {
            throw new IllegalStateException(
               "Exception while looking in JNDI for 'java:comp/env/limousineDao': " + e.getLocalizedMessage());
         }
         System.out.println("Going to Init");
         limousineDao.init();
         return limousineDao;
      }
   }
}

roofimon · **Posted:** Wed Apr 07, 2004 12:40 am

Lastly, This is my Servlet. Please, make any comments on my coding style.

Code:

package com.netplus.workstation.pprincess.module.admin;

import com.netplus.cocoon.struts.AbstractModule;
import com.netplus.cocoon.struts.ActionForm;
import com.netplus.cocoon.struts.ActionForward;
import com.netplus.cocoon.struts.ActionMapping;

import com.netplus.workstation.pprincess.Limousine;
import com.netplus.workstation.pprincess.ejb.LimousineHome;
import com.netplus.workstation.pprincess.ejb.LimousineRemote;
import com.netplus.workstation.pprincess.ejb.LimousineUtil;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.avalon.framework.parameters.Parameters;

public final class LimousineInfo extends AbstractModule {

   public ActionForward perform(ActionMapping mapping, ActionForm form,
                                ServletContext scontext, HttpServletRequest request,
                                HttpServletResponse response, Parameters par)
       throws ServletException {

      LimousineHome limousineHome = null;
      LimousineRemote session = null;
      
      long limId = Long.parseLong(request.getParameter("limousineId"));
      try {
         System.out.println("LimousineInfo was executed");
         limousineHome = LimousineUtil.getHome();
         session = limousineHome.create();
         Limousine limousine = session.findByPrimaryKey(limId);
         request.setAttribute("limousineInfo", limousine);
         return (mapping.findForward("success"));
      } catch(Exception e) {
         getLogger().error(e.toString(), e);
         throw new ServletException("Error performing : " + e.getMessage());
      } finally {

      }
   }
}

igod · **Joined:** Tue Apr 06, 2004 9:15 am **Posts:** 4

Thanks Arin,

It will be a good help for me. I'm just beggining and every simple help will be a great help for me.
But, just a little question more.
Why you use @castor doclet in DAO Impl ?

Paulo

roofimon · **Posted:** Thu Apr 08, 2004 1:13 am

Dear Paulo
I couldn't find @castor in DAO implement, but it's in my Hibernate Implement......Actually, I use castor tag just to transform my obj to XML at presentation layer and we used CASTOR transformer.

strikepollar · **Joined:** Thu Apr 01, 2004 6:28 pm **Posts:** 15

Why not use hibernate with a Pojo, why is waste time following RIDICOULOUS standards if that doesnt make you money????/
THATS my question

roofimon · **Posted:** Mon Apr 12, 2004 11:36 pm

Calm down buddy
Yeah, This standard is quite RIDICOULOUS, however not all of it is bad. Our reason to did this because we was working with Entity(BMP)+Session and we found that BMP cost us lot of time to develop and it's not that simple as well.
We decide to changed but as you know (I though) when people get use to something it is very hard to rapidly change it. "Do a little step" is good to follow. So I did change from BMP -> Hibernate first and it would have some more later on.
Lastly, pardon me my English
Roofimon

Martin Kersten · **Joined:** Tue Mar 16, 2004 5:15 am **Posts:** 33

@roofimon

Take a look at jakarta.apache.org -> commons/logging and log4j. this println is a trouble some approach.

Other more complex hibernate examples are bundled with the spring framework distribution. Check those out! :)

roofimon · **Posted:** Tue Apr 13, 2004 8:36 am

thx
Yeah, I'm reading on both Spring and Logging Framework.

Cheers
Roofimon

ItchyOinker · **Joined:** Thu Apr 29, 2004 12:45 pm **Posts:** 45

arin,

Thanks for the great example! This is a really big help for developing my project. Your code is easy to follow and organized nicely. I notice that methods in the DAO and Session classes return objects through the Limousine interface. Does this increase performance?

I mean, you could alternatively instantiate DAOImpl from Session and call its methods without returning DAOImpl, via the Limousine interface.

I'm not an expert, so I'd greatly appreciate your comments.

Regards,
Itchy