librarymanager.java

struts+h st ruts+h struts+h 这是个英文原吗!

/*
 * Created on 25.11.2004 by HS
 * 
 */
package de.laliluna.library.bl;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.hibernate.Session;
import org.hibernate.Transaction;

import de.laliluna.library.Book;
import de.laliluna.library.Customer;
import de.laliluna.library.HibernateSessionFactory;

/**
 * @author HS
 * 
 * 
 */
public class LibraryManager {

	/**
	 * get all books from the database
	 * 
	 * @return Array of BookValue
	 */
	public Book[] getAllBooks() {
		/* will hold the books we are going to return later */
		List books = new ArrayList();
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		List tmpBooks = session.createQuery(
				"select b from Book as b order by b.author, b.title").list();
		for (Iterator iter = tmpBooks.iterator(); iter.hasNext();) {
			books.add((Book) iter.next());
		}
		tx.commit();

		return (Book[]) books.toArray(new Book[0]);
	}

	/**
	 * get book by primary key
	 * 
	 * @param primaryKey
	 * @return a Book or null
	 */
	public Book getBookByPrimaryKey(Integer primaryKey) {
		/* holds our return value */
		Book book = null;
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		book = (Book) session.get(Book.class, primaryKey);
		tx.commit();
		return book;
	}

	/**
	 * sets the book as borrowed to the user specified in the database
	 * 
	 * @param primaryKey
	 * @param userPrimaryKey
	 */
	public void borrowBook(Integer primaryKey, Integer customerPrimaryKey) {
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		Book book = (Book) session.get(Book.class, primaryKey);
		// only if borrowing of the book is allowed
		if (book.getBorrowallowed()) {
			Customer customer = (Customer) session.get(Customer.class,
					customerPrimaryKey);
			if (book != null && customer != null)
				book.setCustomer(customer);
		}

		tx.commit();
	}

	/**
	 * customer returns a book, relation in the db between customer and book is
	 * deleted
	 * 
	 * @param primaryKey
	 */
	public void returnBook(Integer primaryKey) {
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;
		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		Book book = (Book) session.get(Book.class, primaryKey);

		if (book != null) {
			// session.get returns null when no entry is found
			Customer customer = book.getCustomer();
			if (customer != null) {
				customer.getBooks().remove(book);
				book.setCustomer(null);
			}
		}
		tx.commit();
	}

	/**
	 * updates/creates a book
	 * 
	 * @param bookValue
	 */
	public void saveBook(Book bookValue) {

		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;
		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		Book book;
		if (bookValue.getId() != null && bookValue.getId().intValue() != 0) { // [laliluna]
			// 04.12.2004
			// load
			// book
			// from
			// DB
			book = (Book) session.get(Book.class, bookValue.getId());
			if (book != null) {
				book.setAuthor(bookValue.getAuthor());
				book.setTitle(bookValue.getTitle());
				book.setBorrowallowed(bookValue.getBorrowallowed());
				session.update(book);
			}
		} else // [laliluna] 04.12.2004 create new book
		{
			book = new Book();
			book.setAuthor(bookValue.getAuthor());
			book.setTitle(bookValue.getTitle());
			book.setBorrowallowed(bookValue.getBorrowallowed());
			session.save(book);
		}
		tx.commit();
	}

	/**
	 * deletes a book
	 * 
	 * @param primaryKey
	 */
	public void removeBookByPrimaryKey(Integer primaryKey) {
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();
		tx = session.beginTransaction();
		Book book = (Book) session.get(Book.class, primaryKey);
		if (book != null)
			if (book.getCustomer() != null)
				book.getCustomer().getBooks().remove(book);
		session.delete(book);
		tx.commit();
	}

	/**
	 * returns all customers from the db
	 * 
	 * @return
	 */

	public Customer[] getAllCustomers() {
		/* will hold the books we are going to return later */
		List customers = new ArrayList();
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;
		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		List tmpCustomer = session.createQuery(
				"select c from Customer as c order by c.lastname").list();
		for (Iterator iter = tmpCustomer.iterator(); iter.hasNext();) {
			customers.add((Customer) iter.next());
		}
		tx.commit();
		return (Customer[]) customers.toArray(new Customer[0]);
	}

	/**
	 * gets a customer from the db
	 * 
	 * @param primaryKey
	 * @return the customer class or null, when no customer is found
	 */
	public Customer getCustomerByPrimaryKey(Integer primaryKey) {
		/* holds our return value */
		Customer customer = null;
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		customer = (Customer) session.get(Customer.class, primaryKey);
		tx.commit();

		return customer;
	}

	/**
	 * saves the customers to the db
	 * 
	 * @param customer
	 */
	public void saveCustomer(Customer customer) {
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();
		tx = session.beginTransaction();
		if (customer.getId() == null || customer.getId().intValue() == 0) // [laliluna]
			// 06.12.2004
			// create
			// customer
			session.save(customer);
		else {
			Customer toBeUpdated = (Customer) session.get(Customer.class,
					customer.getId());
			toBeUpdated.setAge(customer.getAge());
			toBeUpdated.setLastname(customer.getLastname());
			toBeUpdated.setFirstname(customer.getFirstname());
			session.update(toBeUpdated);
		}
		tx.commit();
	}

	/**
	 * deletes a customer from the database
	 * 
	 * @param primaryKey
	 */
	public void removeCustomerByPrimaryKey(Integer primaryKey) {
		/* a Hibernate session */
		Session session = null;
		/* we always need a transaction */
		Transaction tx = null;

		/* get session of the current thread */
		session = HibernateSessionFactory.currentSession();

		tx = session.beginTransaction();
		Customer customer = (Customer) session.get(Customer.class, primaryKey);
		if (customer != null) {
			Set books = customer.getBooks();
			for (Iterator iter = books.iterator(); iter.hasNext();) {
				Book element = (Book) iter.next();
				element.setCustomer(null);
			}

			session.delete(customer);
		}
		tx.commit();
	}

}