package com.totsp.example.jpa.dao.plain;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.NoResultException;

import org.apache.log4j.Logger;

import com.totsp.example.jpa.dao.IUserDao;
import com.totsp.example.jpa.exception.DataException;
import com.totsp.example.jpa.model.User;


public class UserDao extends BaseDao implements IUserDao
{   
    private static final Logger LOG = Logger.getLogger(UserDao.class);
    
    private EntityManager manager;

    public UserDao()
    { 
        super();        
        this.manager = emf.createEntityManager();
        LOG.debug("userDao constructed");
        LOG.debug("EntityManager created");
    }

    public User get(long id) throws DataException
    {        
        LOG.debug("get invoked - id = " + id);
        User user = null;
        try
        {
            user = manager.find(User.class, id);        
        }
        catch (NoResultException e)
        {
            LOG.warn(e);
        }
        return user;        
    }

    public User get(String name) throws DataException
    {
        LOG.debug("get invoked - name = " + name);
        User user = null;
        try
        {
            user = (User) manager.createQuery("select a from User a where a.name = ?1").setParameter(1, name).getSingleResult();
        }
        catch (NoResultException e)
        {
            LOG.warn(e);
        }
        return user;
    }

    public List getAll() throws DataException
    {        
        LOG.debug("getAll invoked"); 
        List users = null;
        try
        {
            users = manager.createQuery("select a from User a").getResultList();        
        }
        catch (NoResultException e)
        {
            LOG.warn(e);
        }
        return users;
        
    }
    
    public User update(User user) throws DataException
    {
        LOG.debug("update invoked - user = " + user);
        manager.getTransaction().begin();        
        manager.merge(user);
        manager.getTransaction().commit(); 
        return user;
    }
    
    public void save(User user) throws DataException
    {
        LOG.debug("save invoked - user = " + user);
        manager.getTransaction().begin();   
        manager.persist(user);
        manager.getTransaction().commit();
    }

    public void remove(User user) throws DataException
    {       
        LOG.debug("remove invoked - user = " + user);
        manager.getTransaction().begin();        
        manager.remove(user);
        manager.getTransaction().commit();
    }

    public void finalize() throws Throwable
    {   
        LOG.debug("finalize invoked");
        try
        {
            if (manager != null)
            {
                manager.close();
                LOG.debug("EntityManager closed");
            }
        }
        finally
        {
            super.finalize();
        }        
    }
    
}