/*
 * HibernateFacade.java
 *
 * Created on April 25, 2005, 6:45 PM
 */

package book.hibernate;

import book.business.Book;
import book.business.BookFacade;
import book.exceptions.DatabaseException;
import java.util.List;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

/**
 *
 * @author Sam Vaitheeswaran
 */
public class HibernateFacade implements BookFacade {
    private SessionFactory hibernateFactory;
    
    public book.business.Book getBook(String id) throws DatabaseException {
        Session session = null;
        Transaction tx = null;
        Book book = null;
        try {
            session = hibernateFactory.openSession();
            tx = session.beginTransaction();
            book = (Book)session.load(Book.class, id);
            tx.commit();
        } catch (HibernateException he){
            if(tx != null){
                try {
                    tx.rollback();
                } catch(HibernateException he2){
                    throw new DatabaseException(he2);
                }
            }
            throw new DatabaseException(he);
        } finally {
            if(session != null){
                try {
                    session.close();
                } catch(HibernateException he3){
                    throw new DatabaseException(he3);
                }
            }
        }
        return book;
    }
    
    public void deleteBook(String id) throws DatabaseException {
        // if id is null do not do any processing
        if(id == null){
            return;
        }
        
        Session session = null;
        Transaction tx = null;
        try {
            session = hibernateFactory.openSession();
            tx = session.beginTransaction();
            Book book = (Book)session.load(Book.class, id);
            session.delete(book);
            tx.commit();
        } catch (HibernateException he){
            if(tx != null){
                try {
                    tx.rollback();
                } catch(HibernateException he2){
                    throw new DatabaseException(he2);
                }
            }
            throw new DatabaseException(he);
        } finally {
            if(session != null){
                try {
                    session.close();
                } catch(HibernateException he3){
                    throw new DatabaseException(he3);
                }
            }
        }
    }
    
    public void deleteBook(book.business.Book book) throws DatabaseException {
        // if book is null do not do any processing
        if(book == null){
            return;
        }
        
        Session session = null;
        Transaction tx = null;
        try {
            session = hibernateFactory.openSession();
            tx = session.beginTransaction();
            session.delete(book);
            tx.commit();
        } catch (HibernateException he){
            if(tx != null){
                try {
                    tx.rollback();
                } catch(HibernateException he2){
                    throw new DatabaseException(he2);
                }
            }
            throw new DatabaseException(he);
        } finally {
            if(session != null){
                try {
                    session.close();
                } catch(HibernateException he3){
                    throw new DatabaseException(he3);
                }
            }
        }
    }
    
    public void updateBook(Book book) throws DatabaseException {
        
        Session session = null;
        Transaction tx = null;
        try {
            session = hibernateFactory.openSession();
            tx = session.beginTransaction();
            session.update(book);
            tx.commit();
        } catch (HibernateException he){
            if(tx != null){
                try {
                    tx.rollback();
                } catch(HibernateException he2){
                    throw new DatabaseException(he2);
                }
            }
            throw new DatabaseException(he);
        } finally {
            if(session != null){
                try {
                    session.close();
                } catch(HibernateException he3){
                    throw new DatabaseException(he3);
                }
            }
        }
    }
    
    public void saveBook(Book book) throws DatabaseException {
        
        Session session = null;
        Transaction tx = null;
        try {
            session = hibernateFactory.openSession();
            tx = session.beginTransaction();
            session.save(book);
            tx.commit();
        } catch (HibernateException he){
            if(tx != null){
                try {
                    tx.rollback();
                } catch(HibernateException he2){
                    throw new DatabaseException(he2);
                }
            }
            throw new DatabaseException(he);
        } finally {
            if(session != null){
                try {
                    session.close();
                } catch(HibernateException he3){
                    throw new DatabaseException(he3);
                }
            }
        }
    }
    
    public List listBooks() throws DatabaseException {
        
        Session session = null;
        Transaction tx = null;
        List result = null;
        try {
            session = hibernateFactory.openSession();
            tx = session.beginTransaction();
            Query q = session.createQuery("from Book as book");
            result = q.list();
            tx.commit();
        } catch (HibernateException he){
            if(tx != null){
                try {
                    tx.rollback();
                } catch(HibernateException he2){
                    throw new DatabaseException(he2);
                }
            }
            throw new DatabaseException(he);
        } finally {
            if(session != null){
                try {
                    session.close();
                } catch(HibernateException he3){
                    throw new DatabaseException(he3);
                }
            }
        }
        return result;
    }
    
    public HibernateFacade(SessionFactory factory) {
        hibernateFactory = factory;
    }
    
    public HibernateFacade() throws  DatabaseException {
        try {
            hibernateFactory = new Configuration().configure().buildSessionFactory();
        }  catch (HibernateException he) {
            throw new DatabaseException(he); 
            
        }
    }

}