midpservice.java

本例集中讲解了一下J2ME和J2EE 之间是怎样结合的并通过例子来解释

		    serverError(rev);
		} 
	    }
	}	    
	
    }

    // Parameters: username, password
    void loginUser(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

        try {
            String username = params.nextToken();
            String password = params.nextToken();

            Customer c = findCustomerEJB(username);
            CustomerInformation ci = c.getInformation();
            if (!password.equals(ci.getPassword())) {
                throw new MIDPException(PASSWORD_INCORRECT_ERROR);
            }
            customerInfo = ci;

            out.writeUTF(sessionURL);
        } catch (FinderException fe) {
            throw new MIDPException(USER_NOT_FOUND_ERROR);
        } catch (Exception e) {
            serverError(e);
        }
    }

    // Parameters: <none>
    void displayMovies(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

        try {
            List movies = movieInfo.getMovies(customerInfo.getZipCode());
            out.writeInt(movies.size());
            for (int i = 0; i < movies.size(); i++) {
                Movie movie = (Movie) movies.get(i);
                out.writeInt(movie.getID());
                out.writeUTF(movie.getTitle());
                out.writeUTF(movie.getRating());
                out.writeUTF(movie.getPosterURL());
            }
        } catch (Exception e) {
            serverError(e);
        }
    }
    
    // Parameters: movieID
    void displayLocations(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

        try {
            int movieID = Integer.parseInt(params.nextToken());
            List locations = 
                movieInfo.getLocations(customerInfo.getZipCode(), movieID);
            out.writeInt(locations.size());
            for (int i = 0; i < locations.size(); i++) {
                Location location = (Location) locations.get(i);
                out.writeInt(location.getID());
                out.writeUTF(location.getLocation());
            }
        } catch (Exception e) {
            serverError(e);
        }
    }

    // Parameters: movieID, locationID
    void displayShowtimes(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

        try {
            int movieID = Integer.parseInt(params.nextToken());
            int locationID = Integer.parseInt(params.nextToken());

            List showtimes = movieInfo.getShowtimes(movieID, locationID);
            out.writeInt(showtimes.size());
            for (int i = 0; i < showtimes.size(); i++) {
                Showtime showtime = (Showtime) showtimes.get(i);
                out.writeInt(showtime.getID());
                out.writeUTF(showtime.getShowtime());
            }
        } catch (Exception e) {
            serverError(e);
        }
    }

    // Parameters: showID
    void displaySeatingPlan(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

        try {
            int showID = Integer.parseInt(params.nextToken());

            if (ticketSales != null) {
                ticketSales.cancelSeats();
            }
            ticketSales 
                = createTicketSalesEJB(customerInfo.getUsername(), showID);
            SeatingPlan sp = ticketSales.getSeatingPlan();

            out.write((byte)sp.getRowCount());
            out.write((byte)sp.getRowLength());
            byte[] seats = sp.getSeatData();
            out.write(seats);
        } catch (Exception e) {
            serverError(e);
        }
    }

    // Parameters: showID, row1, seat1, ..., rowN, seatN
    void reserveSeats(DataOutputStream out, StringTokenizer params)
        throws MIDPException {

        try {
            Set seats = new HashSet();
            while (params.hasMoreTokens()) {
                seats.add(new Seat(Integer.parseInt(params.nextToken()), 
                                   Integer.parseInt(params.nextToken())));
            }
            ticketSales.reserveSeats(seats);
        } catch (UnavailableSeatsException use) {
            throw new MIDPException(UNAVAILABLE_SEATS_ERROR);
        } catch (Exception e) {
            serverError(e);
        }
	
    }

    // Parameters: creditCard
    void confirmSeats(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

	int creditCard = Integer.parseInt(params.nextToken());

        try {
            ticketSales.confirmSeats();
        } catch (Exception e) {
            serverError(e);
        } finally {
	    if (ticketSales != null) {
		try {
		    ticketSales.remove();
		    ticketSales = null;
		} catch (RemoteException rem) {
		    serverError(rem);
		} catch (RemoveException rev) {
		    serverError(rev);
		}
	    }
	}
    }

    // Parameters: <none>
    void cancelSeats(DataOutputStream out, StringTokenizer params) 
        throws MIDPException {

        try { 
            ticketSales.cancelSeats();
        } catch (Exception e) {
            serverError(e);
        } finally {
	    if (ticketSales != null) {
		try {
		    ticketSales.remove();
		    ticketSales = null;
		} catch (RemoteException rem) {
		    serverError(rem);
		} catch (RemoveException rev) {
		    serverError(rev);
		}
	    }
	}
    }


    // EJB helper methods

    /*
     * Helper method to instantiate a MovieInfoEJB.
     */
    MovieInfo createMovieInfoEJB() 
        throws CreateException, NamingException, RemoteException {
        MovieInfoHome home = 
            (MovieInfoHome) PortableRemoteObject
            .narrow(new InitialContext()
                .lookup("java:comp/env/ejb/MovieInfo"), 
                    MovieInfoHome.class);
        return (MovieInfo) home.create();
    }

    /*
     * Helper method to instantiate a LocaleInfoEJB.
     */
    LocaleInfo createLocaleInfoEJB() 
        throws CreateException, NamingException, RemoteException {
        LocaleInfoHome home = 
            (LocaleInfoHome) PortableRemoteObject
            .narrow(new InitialContext()
                .lookup("java:comp/env/ejb/LocaleInfo"), 
                    LocaleInfoHome.class);
        return (LocaleInfo) home.create();
    }


    /*
     * Helper method to find TicketSales for the given show.
     */
    TicketSales createTicketSalesEJB(String customerID, int showID) 
        throws CreateException, NamingException, RemoteException {
        TicketSalesHome home = 
            (TicketSalesHome) PortableRemoteObject
            .narrow(new InitialContext()
                .lookup("java:comp/env/ejb/TicketSales"), 
                    TicketSalesHome.class);
        return (TicketSales) home.create(customerID, showID);
    }

    /*
     * Helper method to create a new Customer.
     */
    Customer createCustomerEJB(String username, String password, 
                               String zipCode, String creditCard)
        throws CreateException, DuplicateKeyException, 
               NamingException, RemoteException {
        CustomerHome home = 
            (CustomerHome) PortableRemoteObject
            .narrow(new InitialContext()
                .lookup("java:comp/env/ejb/Customer"), 
                    CustomerHome.class);
        return (Customer) home.create(username, password, 
                                      zipCode, creditCard);
    }

    /*
     * Helper method to find a Customer by his or her username.
     */
    Customer findCustomerEJB(String username) 
        throws FinderException, NamingException, RemoteException {
        CustomerHome home = 
            (CustomerHome) PortableRemoteObject
            .narrow(new InitialContext()
                .lookup("java:comp/env/ejb/Customer"), 
                    CustomerHome.class);
        return (Customer) home.findByPrimaryKey(username);
    }

    /*
     * Some unexpected server error has occurred.
     */
    private void serverError(Exception e) throws MIDPException {
        System.err.println("[TRACE]: Server error: " + e);
        e.printStackTrace();
        throw new MIDPException(SERVER_ERROR);
    }
}