Responsibility for managing the enterprise beans used by the Web client rests with the BeanManager. The other beans- AccountHistoryBean, TransferBean, and ATMBean-are instantiated depending on which request URL is being handled. The BeanManager and CustomerBean components are instantiated for the session and request, respectively. Dispatcher, a servlet, processes requests and forwards them to template.jsp.įinally, the Web client uses logic tags from the JSTL core tag library to perform flow control and tags from the JSTL fmt tag library to localize messages and format currency.Īll the JavaBeans components used in the Web client are instantiated by Dispatcher.The template mechanism consists of three components: The Web client uses a template mechanism implemented by custom tags (discussed in A Template Tag Library) to maintain a common look across all the JSP pages. ATMBean invokes enterprise bean methods and sets acknowledgment strings according to customer input, and AccountHistoryBean massages the data returned from the enterprise beans in order to present the view of the data required by the customer. However, the other JavaBeans components have much richer functionality. In the Duke's Bank application, TransferBean acts as a facade to the TransactionControllerBean enterprise bean. In the Duke's Bookstore application, discussed in Chapters 11 to 22, the BookDB JavaBeans component acts as a front end to a database. In the Duke's Bank application, the JSP pages use enterprise beans to handle interactions with the database and rely on JavaBeans components for interactions with the enterprise beans. To achieve this, most dynamic processing tasks are delegated to enterprise beans, custom tags, and JavaBeans components. The main job of the JSP pages in the Duke's Bank application is presentation.
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