The J2EE BookShop A detailed walk through of the J2EE BookShop

Functional Requirements - repetition The Bookshop is a web shop where the customer can do the following  Customers should log into the system  Customers should be able to browse through all available books  Customers should be able to view detailed information about a particular book

Functional Requirments - repetition  Customers should be able to add and remove books from their shopping cart  When customers want to checkout their order, they should supply shipping information  When checking out, the order should be written in the ORDER table and the different books in the ORDER_ITEMS table

Technical Requirments - repetition Use MVC, Model View Controller The result return from beans or servlet should be XML that’s transformed to HTML with XSLT (use the JSTL tag library). Never print HTML in the beans or the Servlets. Output in JSPs are acceptable Try use a Custom tag, for example to return the shopping cart

Fundamental design ideas The book shop uses these fundamental design ideas  Model View Controller (MVC) is used as the base  All requests should be handled by a single controller servlet  Standard J2EE Security is used to secure the site We don’t implement the security, we only tell the system to use it  All dynamic content should be returned to the view as XML  All XML is transformed into XHTML with XSLT

Fundamental design ideas Static layout can be performed in the JSP pages for simplicity Only control logic in the controller servlet All business logic in Java Beans All presentation logic in JSPs and XSLT The shopping cart is accessed through a Custom Tag

Fundamental design ideas Environment variables (like JDBC Url and the different JSP pages) should be configurable at deploy time, i.e. should be defined in web.xml

web.xml One servlet  Named Shop and mapped as /shop  se.upright.education.uu.pvk.assignmenttwo.servle ts.ShopServlet Five init-param entries  JDBC_URL  CHECKOUT_PAGE  SHOW_PAGE  THANKYOU_PAGEDETAIL_PAGE

web.xml Three Tag Libraries  JSTL – core c.tld  JSTL – xml x.tld  BookShop bookshop.tld

web.xml The URL-pattern /* is secured Only users in the role tomcat is allowed Form-login is used  login.jsp is the login form  login_error.jsp is the error page in case of a login failure

web.xml TheShop /* tomcat NONE FORM /login.jsp /login_error.jsp

Database access All database access is handled by two beans  BookListBean  OrderBean The book list is only fetched once and then added to the application context  Bad performance to get the list for each request  Unnecessary memory usage if each user have a book list of their own  Read-only data

BookBean A JavaBean that represent one book All properties of the book available with getXXX() and setXXX() methods getXml() returns the book in XML format

BookListBean The implementation of the book list A Collection with BookBeans is the actual list When created, the BookListBean() connects to the database and fetches all books getXml() returns the entire book list as XML getXml() uses BookBean.getXml() to build it’s XML representation

ShoppingBean The implementation of the shopping cart Each user should have his own instance of the shopping cart addBook(book, quantity) adds a book to the cart  If the exists in the cart, only increase the quantity removeBook(id, quantity) removes a book  If the quantity to remove is more or equal to the present, remove the book, otherwise decrease the quantity in the cart

ShoppingBean getCart() returns the Collection that holds the actual cart getXml() returns the shopping cart as XML clear() removes all books from the cart

OrderBean Used to create a new order based on the shopping cart and the shipping information entered by the user The order is written to the ORDER-table The different books are written to the ORDER_ITEM table Explicit transaction handling is used  Inserting an order is one operation  Each book is one operation  All operations in one transaction, i.e. write the order and all books, or write nothing

ShopingCartTag The implementation of the Custom tag to output the shopping cart Uses ShoppingBean.getXml() to get the cart

XML – the book 1 Javaprogramming Fredrik Alund Bla bla bla

XML – the book list 1 Javaprogramming Fredrik Alund Bla bla bla 2 Javaprogramming2 Kalle Svensson Bla bla bla

XSL files booklist_xsl.xslt  Format the book list  BookListBean.getXml() bookdetail_xsl.xslt  Format the details about a particular book  BookBean.getXml() shoppingcart_xsl.xslt  The shopping cart shown in the show page  ShoppingBean.getXml() shoppingcart_checkout_xsl.xslt  The shopping cart shown in the checkout page  ShoppingBean.getXml()