catalogbean.java

来自「java编程最好的书籍,感觉对初学者或者中级java人员帮助很大」· Java 代码 · 共 108 行

package examples;

import javax.ejb.*;
import java.rmi.RemoteException;
import java.util.*;
import javax.naming.*;
import javax.rmi.PortableRemoteObject;
/**
 * This catalog Stateless Session Bean retrieves a list of Bookitems.
 * BookItem has Book Id, name of the Book and description
 */
public class CatalogBean implements SessionBean {
    
    /*
	 * Although this is a stateless session bean, we
	 * do have state - the session context.  Remember
	 * that stateless session beans can store state, they
	 * just can't store state on behalf of particular
	 * clients.
	 */
	private SessionContext ctx;
  	//----------------------------------------------------
	// End EJB-required methods
	//----------------------------------------------------
    
    /**
     * Returns the Bookitem for the given Book id
     */
    public BookItem getBookItem(String bookId){
        try{
                Context ctx = new InitialContext();
                BookHome bookHome = (BookHome)
                    PortableRemoteObject.narrow(
                        ctx.lookup("BookHome"), BookHome.class);
                Book book=bookHome.findByPrimaryKey(bookId);
                /*
                 * Creates and returns the Bookitem
                 */
                return new BookItem(book.getBookID(),book.getName(),
                                book.getBasePrice(),book.getDescription());
            }catch (Exception e) {
                throw new EJBException(e);
            }
    }
    
    /**
     * Returns the list of Bookitems
     */
    public Vector getBookItemList(){
        try{
                Context ctx = new InitialContext();
                BookHome bookHome = (BookHome)
                    PortableRemoteObject.narrow(
                            ctx.lookup("BookHome"), BookHome.class);
                Collection books=bookHome.findAllBooks();
                Enumeration items = Collections.enumeration(books);
                Vector bookItems=new Vector();
                    while (items.hasMoreElements()) {
                        Book book= (Book) items.nextElement();
                        /*
                         * Creates a new Bookitem
                         */
                        BookItem p=new BookItem(book.getBookID(),book.getName(),
                                        book.getBasePrice(),book.getDescription());
                        bookItems.add(p);
                    }
                /*
                 * Returns the vector of Book items
                 */
                return bookItems;
            }catch (Exception e) {
                throw new EJBException(e);
            }
    }
        
    //----------------------------------------------------
	// Begin EJB-required methods.  The methods below are
	// called by the Container, and never called by client
	// code.
	//----------------------------------------------------
   
	public void ejbCreate() throws RemoteException {
		System.out.println("ejbCreate() called.");
	}
  
	public void ejbRemove() {
		System.out.println("ejbRemove() called.");
	}

	public void ejbActivate() {
		System.out.println("ejbActivate() called.");
	}

	public void ejbPassivate() {
		System.out.println("ejbPassivate() called.");
	}
   
    /**
	 * Associates this Bean instance with a particular
	 * context.
	 */
	public void setSessionContext(SessionContext ctx) {
		System.out.println("setSessionContext() called");
		this.ctx = ctx;
	}

}