This end to end scenario discribes developing of very simple Library
Reservation System. It covers j2ee features which are possibe to use in
NetBeans IDE 5.5 (version for NetBeans 4.1 is here).
This application consists of EJB module with one web
service, which is used for reservation of book in libarry. We will
create database tables in bundled Java DB database, then we will
generated CMP Entity Beans from this database and finally we will
create web service.
Library sources are available here.
Database setup
Start bundled Java DB.
Tools | Java DB Database | Start Java DB Server
Create new database .
Tools | Java DB Database | Create Java DB Database, call it library
and use tester as user name as well as password.
Create tables with sample data.
Click on Open button and open library-javadb.sql.
Choose connection to created library DB and click on 'Execute All' button.
Creating IDE project
Create newJ2EE 1.4 EJB Module project with name
"Library".
Generate CMP Entity Beans from
Database. Right-click on Library project and select New ->
CMP Entity Beans from Database. Create new Data source jdbc/library
for jdbc:derby://localhost:1527/library connection, Add
All tables and click on Next, enter package library
and let both checkboxes selected and click on Finish. Four Entity
Beans are created.
Create Book DTO.
Right-click on BookEB and select Generated DTO from popup menu.
Create Service Locator. Open
New File Wizard, select category Enterprise, file type
Caching Service Locator, enter ServiceLocator as
locator Name, package service and
press Finish.
Create Web Service. Open
New File Wizard, select category Web Services, file type Web Service,
enter "ReservationService" as Web Service Name, package "service" and
press Finish.
Writing Web Service
Call EJB. Select
"Enterprise Resources -> Call Enterprise Bean" from popup menu and
select BookEB. Do the same for BookCopyEB, ReservationEB and
LibraryUserEB.
Write login method.
private LibraryUserLocal login(String username, String password) throws java.rmi.RemoteException {
LibraryUserLocal user;
try {
user = lookupLibraryUserBean().findByPrimaryKey(username);
} catch (FinderException e) {
throw new RemoteException("Authentication failed: Invalid username or password.");
}
if (user == null || !user.getPassword().equals(password)) {
throw new RemoteException("Authentication failed: Invalid username or password.");
}
return user;
}
Write convertToBookDTOArray
method.
private library.BookDTO[] convertToBookDTOArray(Collection collection) {
if (collection == null || collection.isEmpty()) {
return null;
}
BookDTO books[] = new BookDTO[collection.size()];
int index = 0;
Iterator it = collection.iterator();
while (it.hasNext()) {
BookLocal bookBean = (BookLocal)(it.next());
BookDTO bookDTO = new BookDTO();
bookDTO.populate(bookBean);
books[index++] = bookDTO;
}
return books;
}
Create getBooksByTitle operation.
Select "Web Service -> Add Operation" from
popup menu. Create this operation:
Add Finder Method to
BookCopyEB. Open BookCopyEB and select "EJB Methods -> Add Finder
Method" from popup menu. Call it findByISBN, use following EJBQL:
SELECT OBJECT(o) FROM BookCopy o WHERE o.isbn.isbn = ?1,
add String isbn parameter and press OK.
Add Finder Method to
BookCopyEB. Open BookCopyEB and select "EJB Methods -> Add Finder
Method" from popup menu. Call it findReservedBooks, use following EJBQL:
SELECT DISTINCT OBJECT(o) FROM BookCopy o, IN (o.reservationBeanCollection) AS r
WHERE o.isbn.isbn = ?1 AND ((r.reservedFrom <= ?2 AND r.reservedTo >= ?2)
OR (r.reservedFrom <= ?3 AND r.reservedTo >= ?3) OR (r.reservedFrom >= ?2
AND r.reservedTo <= ?3)),
add String isbn, java.sql.Date from, java.sql.Date to
parameter and press OK.
Add Select method. Open
ReservationEB and select "EJB Methods -> Add Select Method" from
popup menu. Call it ejbSelectMaxId, use following EJBQL:
SELECT MAX(o.id) FROM Reservation o and press OK.
Add Home method. Open
ReservationEB and select "EJB Methods -> Add Home Method" from popup
menu. Write name "maxId", return type "int". Write method code:
public int ejbHomeMaxId() {
//TODO implement ejbHomeMaxId
try {
return ejbSelectMaxId();
} catch (FinderException e) {
return 0;
}
Add Create method. Open
ReservationEB and select "EJB Methods -> Add Create Method" from popup
menu, add Integer id, Date from, Date to, BookCopyLocal bookCopy,
LibraryUserLocal user parameters, press OK and implement added
create and postCreate methods:
public Integer ejbCreate(Integer id, Date from, Date to, BookCopyLocal bookCopy, LibraryUserLocal user)
throws CreateException {
//TODO implement ejbCreate
setId(id);
setReservedFrom(from);
setReservedTo(to);
setReturned(null);
return null;
}
public void ejbPostCreate(Integer id, Date from, Date to, BookCopyLocal bookCopy, LibraryUserLocal user)
throws CreateException {
//TODO implement ejbPostCreate
setUsername(user);
setBookcopyId(bookCopy);
}
Create operation. Open
ReservationService, add new operation there:
public boolean reserve(String username, String password, String isbn, String from, String to)
throws javax.ejb.FinderException, javax.ejb.CreateException, java.rmi.RemoteException {
// TODO implement operation
LibraryUserLocal user = login(username, password);
try {
DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.US);
java.sql.Date f = new java.sql.Date(df.parse(from).getTime());
java.sql.Date t = new java.sql.Date(df.parse(to).getTime());
Collection reservedBooks = lookupBookCopyBean().findReservedBooksEntity(isbn, f, t);
// get all books for this isbn
Iterator it = lookupBookCopyBean().findByISBN(isbn).iterator();
while(it.hasNext()){
BookCopyLocal bookCopy = (BookCopyLocal)it.next();
if (!reservedBooks.contains(bookCopy)){
ReservationLocal reservation = lookupReservationBean()
.create(
new Integer(lookupReservationBean().maxId()+1),
f, t, bookCopy, user);
return true;
}
}
return false;
} catch (ParseException e) {
throw new RemoteException("Date parse error: "+e.getMessage());
}
}
Create Message Handler.
Open New File Wizard, select Web Services category and create new
Message Handler. Name it ReservationMessageHandler, and create it in
package service.
Set Message Handler.
Right-click on ReservationService node and select Configure Handlers
popup menu. Add newly created Message Handler.
Test functionality
Build project
Deploy project
Create new temporary web/ejb project with web service client
for ReservationService
Web Service References -> ReservationService ->
ReservationServiceSEIPort.
Double-click on getBooksByAuthor node.
Enter parameters: "Tom", "tom", "Douglas Adams".
Click on submit. You will get all books from Douglas Adams. Clock
dialog.
