SilverBooks

Introduced in SilverStream 3.0, SilverBooks is a Web-based electronic commerce application that simulates an online bookstore. Users can interact with this application to purchase books from SilverBooks Corporation, a fictitious bookseller. There are two interfaces: an Internet and an Intranet.

This sample application resides in the SilverBooks3 database.

SilverBooks is written using Java servlets, which extend Web server functionality by responding to HTTP requests on URLs that are assigned to the servlets. One advantage of using servlets is that they are written entirely in Java and, therefore, work across platforms.

SilverBooks synthesizes a variety of state-of-the-art technologies in one full-featured application, including persistent session-level failover, enterprise JavaBeans, and credit card order processing. A feature called Behind the Scenes exposes these technologies for users in a context-sensitive way as they interact with SilverBooks.

This page covers the following topics:

• Two interfaces
• Technologies used in SilverBooks
• Credit card order processing
• Behind the scenes
• Getting started

    For more information about servlets, see Using Servlet Business Object in the Programmer's Guide.

Two interfaces   

The SilverBooks application provides two interfaces: An Internet and an Intranet. Each of these interfaces serves a different user base with functions tailored to their unique needs.

Internet   

The SilverBooks Internet component provides the following electronic commerce functions for the general public:

• Book search
• Shopping cart
• Check out
• Credit card order processing

The SilverBooks internet is implemented using HTML pages that execute on the server. HTML is a technology that is more portable than Java in an internet environment where user configurations are not known and can run the gamut of technologies.

The Internet starts up by default on pgSilverBooks.html when you run the SilverBooks application. This home page provides access to search engines -- including full-text search -- for browsing inventory by various categories, to a mechanism for creating and querying accounts, and to a shopping cart for ordering products.

Intranet   

The Intranet is designed for internal users -- the employees of the SilverBooks corporation. Within the Intranet, SilverBooks employees can perform the following back office functions:

• Viewing orders
• Managing employee information
• Maintaining the book catalog

This corporate Intranet is implemented as a Java application running in SilverJRunner on a client machine. The application is launched from the form frmIntranet in the SilverBooks3 database. Java can be used here because users are internal and, therefore, their system environments can be configured to support state-of-the-art Java capabilities.

SilverJRunner is a pure Java dynamic application loader that can run in any Java 2 compliant environment. When running a Java application, SilverJRunner automatically downloads and caches the required SilverStream forms on the local hard drive. During this process, SilverJRunner automatically installs on the client machine any changes that were made to the application.

Technologies used in SilverBooks    

SilverBooks incorporates SilverStream technologies that solve a variety of application challenges, as summarized in this section. For more detailed explanations of the technologies that power this application, take a look at the SilverBooks Behind the Scenes component.

• Persistent session-level failover: Persistent session-level failover is the ability to retain temporary user information (state) when servers fail. To provide this capability, applications must store enough information to recreate user state in a persistent storage repository such as a database or file system shared by servers in a cluster.

  SilverBooks maintains critical data for each user's shopping cart in a persistent object store. Three SilverStream classes are used to manage user state:

  • AgoPersistentStateManager
  • AgoPersistentStoreManager
  • AgoPersistentStateConst

  To support session-level failover, the SilverBooks application uses a business object invPersistentStoreManager that extends the AgoPersistentStoreManager class to specify where and how user state will be stored as persistent data. In this case, the data is stored in a table called AgPersistentState in the SilverBooks3 database.

  The AgoPersistentStateManager class provides methods that let users read data from and write data to the persistent store. The Shopping Cart servlet srvltShoppingCart.html calls a method on an AgoPersistentStateManager object, which evaluates the current application state. If application state needs to be recovered, the method instantiates a new AgoPersistentStateManager whose state is restored from the AgPersistentState table.

  You can see persistent session-level failover in action on the Shopping Cart Page pgShoppingCart.html, which shows you the contents of your shopping basket at any time during your session.

      To learn how to implement session-level failover using a live example, go to Application Techniques> HTML Client Techniques in the help system: Implementing Persistent Session-Level Failover.

• Credit card order processing: The SilverBooks application uses two servlets to process orders in conjunction with an outside vendor, iTransact. See Credit card order processing to learn more about how SilverBooks implements this capability and how to set up a test merchant account.
• EJB session beans: The servlet that generates the SilverBooks Shopping Cart page pgShoppingCart uses EJB session beans to keep track of the shopping cart values.

      For more information about EJB session beans, see EJB Session Bean Quick Start in Getting Started and Writing Session Beans in the Programmer's Guide.

• Swing controls: The SilverBooks Intranet uses Swing controls on its forms. SilverStream allows you to implement standard Swing controls or SilverStream subclasses of standard Swing controls, which add advanced capabilities such as client-side data binding and event-driven data validation. For example, the Authors form frmAuthors uses the SilverStream subclass of the Swing JList control to display a list of authors based on selection criteria.

      For more information about working with Swing controls, see Programming Forms in the Programmer's Guide.

• Page bean: The category browser in the upper left portion of the Internet home page is implemented as a page bean -- a JavaBean that is written as a custom page control. At runtime, page beans react to events on the page and produce HTML in line. In SilverBooks, the page bean dynamically displays a tabular listing of the book category and subcategories selected by the user.

      For more information about JavaBeans, see Using Utility Classes, JAR Files, and JavaBeans in the Programmer's Guide.

• E-mail order verification: When users create an order in the SilverBooks Internet, they will receive confirmation via e-mail if they enable this feature in Intranet preferences.
• Subpages: SilverBooks uses subpages to display different data, depending on what a user selects on the home page. Subpages are pages that are placed inside a parent page. They provide a convenient way to reuse common elements among pages.

      For more information about subpages, see Programming Pages in the Programmer's Guide.

• Hidden tab panels: The home page uses hidden tab panels to selectively display subpages in response to different user actions, such as searching for books, viewing book details, or navigating subject categories. Different page elements are placed on each tab, which are hidden or exposed as needed to respond to user requests.

      For more information about tab panels, see Programming Pages in the Programmer's Guide.

• Table versioning: When SilverBooks employees modify the Books database table by entering changes in the Intranet Book Maintenance form, frmBookMaintenance, SilverStream's versioning technology tracks these modifications in a separate table. The use of versioning allows SilverBooks employees to roll back to previous versions as needed and create an approval cycle for content publishing.

      For more information about table versioning, see Using Table-Modified Business Objects in the Programmer's Guide.

• Data binding: Controls on forms -- such as the Intranet Book Maintenance form frmBookMaintenance and pages -- such as the Internet Book Detail page pgBookDetail, are bound to data in the Books table columns. Data binding allows the application to handle all user events and data updates in a batched sequence.

      For more information about data binding, see Data Access Basics in the Programmer's Guide.

• Client-side data caching: In the SilverBooks intranet, the application server sends data to forms in a background thread so users can continue to work as data is transferred to the client.

      For more information about data caching, see Data Access Basics in the Programmer's Guide.

• GUI controls in views: SilverStream views can contain dynamic controls such as data-bound radio buttons, combo boxes, and check boxes. For example, the Categories tab in the Book Maintenance form frmBookMaintenance displays a view that contains check boxes that indicate which book categories are currently featured in the catalog.
• HTML controls: The SilverBooks application uses HTML controls to combine structured data (from the database) with rich content (formatted data from HTML descriptions) on a single page. You can find an HTML control on the Book Detail page pgBookDetail, accessed when a user clicks a book title on the SilverBooks Internet home page. This HTML control displays the descriptions that are entered by SilverBooks employees on the Book Maintenance form frmBookMaintenance in the Intranet portion of the application.

      For more information about using HTML controls on pages, see Page Designer in the Tools Guide.

• Servlet HTTP Session: Each SilverBooks user has a session object on the server that keeps track of their shopping cart values for the duration of their application session.

      For more information about using HTTP session objects, see Triggered Object Basics in the Programmer's Guide.

Credit card order processing   

The SilverBooks application is designed to work with an outside vendor, iTransact, for credit card order processing. The interface is an HTML form containing hidden and visible fields that is submitted to iTransact's CGI scripts.

This section describes how the process works and how to configure your system to exercise this functionality.

How credit card order processing works   

To build the HTML form and transmit the information to iTransact, Silver Books provide two servlets:

• srvltCreditCards creates the HTML form with the appropriate order information when users check out their purchases at the SilverBooks Internet. Then, this servlet posts the order information to a second servlet srvltCreditTransact to record the data in SilverBooks.
• srvltCreditTransact creates a new order in SilverBooks and builds a hidden HTML form based on the information posted by srvltCreditCards. If there is a network connection, srvltCreditTransact generates JavaScript to submit the form to iTransact; if there is no connection, the servlet generates a "dummy" order confirmation page.

When an order is placed, an e-mail is sent to the customer and the merchant. A mail object listens for the merchant e-mail, parses it to find the credit card authorization, then inserts that authorization into SilverBooks.

How to configure your system for credit card order processing   

To try out credit card order processing in SilverBooks, you must set up a test account with iTransact and enable the mail object.

To set up a test account with iTransact:

1. In a browser, go to iTransact's Web site at http://www.itransact.com/merchant/test.html and follow instructions.

   You will receive a merchant ID via e-mail.

2. Start up the SilverBooks Intranet by running the form frmIntranet in SilverJRunner from the SilverBooks3 database.

   For more information on running the SilverBooks Intranet, see Getting started.

3. In the Intranet form, select System Preferences from the Edit menu.
4. Select the Use iTransact for Credit Card Processing check box, enter the iTransact merchant ID you just received via e-mail, and click OK.

To enable the mail object:

1. Set up a new e-mail account for receiving credit card orders in the SilverStream Management Console (SMC).

   For more information about using the SMC, see Administration Overview in the Administrator's Guide.

2. Open the mail object com.silverbooks.mail.mailReceiver by following these steps:
   • In the left pane of the main Designer, expand the SilverBooks3 database and select Objects.
   • In the right pane, navigate to com.silverbooks.ejb.mail.mailReceiver and click the Design icon:

     

     The Business Object Designer opens.

   • Double-click Triggers to open the Triggers property sheet.
   • Click the Mail Account button and add the account you just created, then close the Business Object Designer.

Behind the scenes   

SilverBooks includes a Behind the Scenes function that provides detailed, context-sensitive descriptions of the technologies underlying the forms and pages that make up this application.

To invoke Behind the Scenes:

1. On a page, click the Behind the Scenes link on the banner:

   

2. On a form, select the Display Behind the Scenes Window check box:

   

The Behind the Scenes window opens, as in this example:

Getting started   

To get started exploring the SilverBooks application, follow these steps:

1. Install and run the SilverBooks3 database.

   The Internet home page opens in your browser, as shown:

   

2. Interact with the SilverBooks Internet by:
   • Searching book titles, authors, and subjects
   • Creating an account
   • Adding items to your shopping cart
   • Placing orders
3. Launch the SilverBooks Intranet by following these steps:
   • In the left pane of the main Designer, expand the SilverBooks3 database and select Forms.
   • In the right pane of the main Designer, select frmIntranet and click the Run icon:

     

     The Intranet portion of the application opens in SilverJRunner, as shown:

     

4. Interact with the SilverBooks Intranet by viewing order data, and updating information about books, authors, categories, publishers, employees, and customers.