studentfacadeejb.java

学生注册— 本模块允许新的学生创建和维护他们的帐户信息

package day21ex.studentfacade;

import java.util.*;
import java.rmi.*;
import javax.rmi.*;
import javax.naming.*;
import javax.ejb.*;

import day21ex.enrollmentcart.*;
import day21ex.signon.*;
import day21ex.course.*;
import day21ex.order.*;
import day21ex.orderlineitem.*;
import day21ex.messagesender.*;
import day21ex.student.*;
/* day 21 exercise */
import day21ex.enrollment.*;

public class StudentFacadeEJB implements SessionBean  {
   private SessionContext ctx;
   String  login;
   EnrollmentCart cart;
   public StudentFacadeEJB() {
      print("The container created this instance.\n");
      login = null;
   }
   public void setSessionContext(SessionContext ctx) {
      print("The container called the setSessionContext method ");
      print("to associate session bean instance with its context.\n");
      this.ctx = ctx;
   }
   public void ejbCreate() throws CreateException {
      print("The container called the ejbCreate method.\n");
      cart = getEnrollmentCart();
   }
   public void ejbActivate() {
      print("This instance has just been reactivated.\n");
   }
   public void ejbPassivate() {
      print("The container intends to passivate the instance.\n");
   }
   public void ejbRemove() {
      print("This instance is in the process of being removed ");
      print("by the container.\n");
   }
   public void addUser(String login, String password)  throws RemoteException {
      SignOn signOn = getSignOn();
      signOn.addUser(login, password);
      this.login = login;
   }

   public void addStudent(String loginName, String password, String firstName,
    String lastName, String address, String emailAddress) throws RemoteException  {
      try {
      StudentLocalHome home = getStudentLocalHome();
      addUser(loginName, password);
      StudentLocal student =  home.create(loginName, firstName,
                                          lastName,  address,  emailAddress);
      }catch (Exception e) {
         throw new EJBException(e);
      }

   }

      
   public boolean validateUser(String login, String password) 
      throws InvalidLoginException, RemoteException {
      SignOn signOn = getSignOn();
      boolean status = signOn.validateUser(login, password);
      if ( status )
      {
         this.login = login;
      }
      return status;
   }
   public void addCourses(String[] courseIds) throws RemoteException {
      print("The container called addCourses method.\n");
      if ( courseIds == null) {
         return;
      }
      cart = getEnrollmentCart();
      cart.addCourses(courseIds);
   }
   public Collection getCartItems() throws RemoteException {
      cart = getEnrollmentCart();
      ArrayList items = new ArrayList();
      Collection collection =  cart.getCourses();
      Iterator it = collection.iterator();
      while (it.hasNext()) {
         String courseId = (String)it.next();
         CourseItem item = null;
         try {
            CourseItem ci = getCourseItemDetails(courseId) ;
            items.add(ci);
         } catch (Exception cce) {
            System.out.println("exception  caught: " + cce);
         }
      }
      return items;
   }
   public void empty() throws RemoteException {
      cart = getEnrollmentCart();
      cart.empty();
   }
   void print(String s) {
      System.out.println("StudentFacadeEJB:"+ s);
   }
   public CourseItem getCourseItemDetails(String courseId) throws NamingException, FinderException {
      Context ctx = new InitialContext();
      CourseLocalHome courseHome = (CourseLocalHome)
         PortableRemoteObject.narrow(
            ctx.lookup("day21ex/Course"), CourseLocalHome.class);
      CourseLocal course=courseHome.findByPrimaryKey(courseId);
      CourseItem item=new CourseItem(course.getCourseId(),course.getName(),
                                     course.getFee());
      return item;
   }

   public Vector getCourseItemList(){
      try{
         Context ctx = new InitialContext();
         CourseLocalHome courseHome = (CourseLocalHome)
            PortableRemoteObject.narrow(
               ctx.lookup("day21ex/Course"), CourseLocalHome.class);
         Collection courses=courseHome.findAllCourses();
         Enumeration items = Collections.enumeration(courses);
         Vector courseItems=new Vector();
         while (items.hasMoreElements()) {
            CourseLocal course= (CourseLocal) items.nextElement();
            CourseItem p=new CourseItem(course.getCourseId(),course.getName(),
                                        course.getFee());
            courseItems.add(p);
         }
         return courseItems;
      }catch (Exception e) {
         throw new EJBException(e);
      }
   }
   public String placeOrder() {
      try {
         print("placeOrder called\n");
         OrderLocalHome home=getOrderLocalHome();
         String orderID = makeUniqueID();
         OrderLocal order=home.create(orderID, login ,"unverified",100 );
         Vector orderItems=addOrderLineItems(order);
         order.setLineItems(orderItems);
         sendMessage(orderID);
         cart.empty(); // clear shopping cart
         return orderID;
      } catch (Exception e) {
         throw new EJBException(e);
      }
   }

   /* day 21 exercise */
   public Collection getStudentEnrollments() {
      Collection collection = new ArrayList();
      CourseLocal course;
      StudentLocal student;
      EnrollmentLocal enrollment;
      try {
         EnrollmentLocalHome home= getEnrollmentLocalHome();
         Collection enrollments = home.findStudentEnrollments(login);
         Iterator it = enrollments.iterator();
         while( it != null  && it.hasNext() ) {
            enrollment = (EnrollmentLocal) it.next();
            try {
            course = enrollment.getCourse();
            student = enrollment.getStudent();
            collection.add( new EnrollmentDetails( 
                               enrollment.getEnrollmentId(),
                               student.getStudentId(), 
                               course.getCourseId(),
                               course.getName() ) );
            } catch (Exception e) {
               e.printStackTrace();
               System.err.println(e);
            }
         }
      } catch(FinderException fe) {
         print("FinderException while getStudentEnrollments :" +
                            fe.getMessage() + "\n" );
         throw new EJBException("Unable to find enrollment"+
                            " for student: " + login +
                             fe.getMessage());
      } catch(NamingException ne) {
         print("NamingException while getStudentEnrollments :" +
                            ne.getMessage() + "\n");
         throw new EJBException("NamingException while looking "
                     + "for enrollments of student: " + login +
                     ne.getMessage());
      } catch(Exception e) {
         print("Exception while getStudentEnrollments :" +
                            e.getMessage() + "\n");
         throw new EJBException("Exception while looking "
                     + "for enrollments of student: " + login +
                     e.getMessage());
      }
      return collection;      
   }

   private Vector addOrderLineItems(OrderLocal order){
      try{
         Context ctx = new InitialContext();
         OrderLineItemLocalHome orderLineItemLocalHome = (OrderLineItemLocalHome)
            PortableRemoteObject.narrow(
               ctx.lookup("day21ex/OrderLineItem"), OrderLineItemLocalHome.class); 
         CourseLocalHome courseHome = (CourseLocalHome)
            PortableRemoteObject.narrow(
               ctx.lookup("day21ex/Course"), CourseLocalHome.class);                
         Collection items =  getCartItems();
         Iterator it = items.iterator();
         Vector orderItems=new Vector();
         while( it.hasNext() ) {
            CourseItem item = (CourseItem) it.next();
            CourseLocal course=courseHome.findByPrimaryKey(item.getCourseId());
            String id = makeUniqueID();
            OrderLineItemLocal orderLineItem = 
               orderLineItemLocalHome.create(id, order, course,item.getFee()) ;
            orderItems.add(orderLineItem);
         }
         return orderItems;
      } catch (Exception e) {
         throw new EJBException(e);
      }
   }
   private void sendMessage(String message) throws Exception{
      try{
         print("sendMessage called\n");
         MessageSender sender=new MessageSender();
         sender.sendAMessage(new InitialContext(), message);
      } catch(Exception e){
         throw new EJBException(e);
      }
   }
   private String makeUniqueID(){
      return new Long(System.currentTimeMillis()).toString();
   }


   private OrderLocalHome getOrderLocalHome(){
      try{
         Context ctx = new InitialContext();
         OrderLocalHome home = (OrderLocalHome)
            ctx.lookup("day21ex/Order");
         return home;
      } catch (Exception e) {
         throw new EJBException(e);
      }
   }
   private StudentLocalHome getStudentLocalHome(){
      try{
         Context ctx = new InitialContext();
         StudentLocalHome home = (StudentLocalHome)
            ctx.lookup("day21ex/Student");
        return home;
      } catch (Exception e) {
         throw new EJBException(e);
      }
   }
   SignOn getSignOn(){
      SignOn signOn = null;
      try {
         Context ic = getInitialContext();
         Object o = initialContext.lookup("day21ex/SignOn");
         SignOnHome home = (SignOnHome) 
            javax.rmi.PortableRemoteObject.narrow(o, SignOnHome.class);
         signOn =   home.create();

      } catch (Exception e) {
         print(e.toString());
         throw new EJBException(e);
      }
      return signOn;
   }
   EnrollmentCart  getEnrollmentCart(){
      if ( cart != null ) {
         return cart;
      }
      try {
         Context ic = getInitialContext();
         Object o = initialContext.lookup("day21ex/EnrollmentCart");
         EnrollmentCartHome home = (EnrollmentCartHome) javax.rmi.
            PortableRemoteObject.narrow(o, EnrollmentCartHome.class);
         cart = home.create();

      } catch (Exception e) {
         print(e.toString());
         throw new EJBException(e);
      }
      return cart;
   }

   /* day 21 exercise */
   private EnrollmentLocalHome getEnrollmentLocalHome() 
                                   throws NamingException {
        InitialContext initial = new InitialContext();
        Object o = initial.lookup("day21ex/EnrollmentLocal");
        return ((EnrollmentLocalHome) o);
    }

   Context getInitialContext() throws NamingException {
      if ( initialContext == null ) {
         initialContext = new InitialContext();
      }
      return initialContext;
   }
   Context initialContext = null;


}