How to Use this Book
J2EE Applications and BEA WebLogic Server contains 15 chapters, each of which covers one phase of developing Web-based applications using J2EE and WebLogic Server. Each chapter is organized around a particular Java Enterprise technology that you use to create a component of the WebAuction application, an online auction site that functions as the core example set for this book. The discussion of EJBs, which are the major players in J2EE application development, spans three chapters.
Each chapter notes where an application module fits in an overall application design; how to plan for efficient implementation; the specifics of the example implementation; and recommendations for “best practices” that can guide the implementation of a similar component at your site.
The Enterprise Java APIs and associated APIs that are part of the J2EE specification are discussed in this book in the approximate order in which a developer might use them. However, each technology is described and illustrated without dependencies on material covered in any other chapter.
Road Map
Whether you're an experienced Java developer or a novice, we assume that you're just getting started with developing applications for an application server. Because individual application development styles differ, each chapter is self-contained. You can read the chapters in the order that best suits your development style. The sequence of chapters moves generally from the simpler technologies to the more complex technologies: For example, the EJB and Java Message Service (JMS) chapters (Chapters 7–10) build on concepts learned in the Remote Method Invocation (RMI)/Java Naming and Directory Interface (JNDI) and Java Database Connectivity (JDBC) chapters (Chapters 5 and 6).
After getting a basic idea of the concepts and best practices for each technology, the developer can begin to design some of the major modules, such as the EJBs for the server-side logic, or the JSPs for the user interface.
In narrative form, the chapters follow this sequence:
First, the developer can prototype the user interface, coding the server-side presentation logic in servlets (Chapter 3) or JSPs (Chapter 4).
When the basic outline of the application behavior is known, the developer can plan for database connectivity with JDBC and transactions (Chapter 5).
As application modules emerge, the developer sets up the central registry for object and method names, and the framework for RMI (Chapter 6).
In order to ensure efficient performance when executing an application over a cluster of WebLogic Servers, the developer uses the JMS protocol to set up the middleware-oriented messaging layer to sequence and manage correct object behaviors (Chapter 7).
To ensure application component independence and to take maximum advantage of the WebLogic Server container's services, the developer codes the EJBs, which are at the heart of the application's functionality ((Chapters 8–10)).
To include email functionality, the developer connects the application to Internet mail using the JavaMail protocol (Chapter 11). It is also necessary to design and code the appropriate levels of security (Chapter 12), which can be done with a combination of WebLogic Server features and J2EE security functions.
After unit testing, the developer plans for deployment of the completed application, surveying the hardware and software elements that need to interoperate when an application is deployed (Chapter 13). After the deployment design, methodology, and tools have been surveyed, the developer compiles, tests, and deploys the completed application (Chapter 14).
As appropriate to compare performance of this application to a previous version or to stated performance goals, the developer uses a capacity planning guide to assess the capacity of the production application and the deployment environment (Chapter 15).
Chapter Summaries
For your reference, here are the chapter summaries:
Chapter 1, Introduction, summarizes the features and benefits of the BEA WebLogic Server, and gives an overview of the book and its stylistic conventions.
Chapter 2, Overview of J2EE Technologies, surveys the major J2EE technologies to provide an orientation to the rest of the book.
Chapter 3, Building Presentation Logic with WebLogic Server Servlets, covers the construction of a user interface module with a servlet. Although servlets are not used in the WebAuction application, prototyping the behavior of the user interface is discussed as the logical way to begin the WebAuction application and to capture expected functionality.
Chapter 4, Using WebLogic Server JavaServer Pages, continues the construction of the user interface using JSP scripts. JSPs are used for all of the WebAuction application's interactions with users. This chapter illustrates best practices for coding JSPs with several example JSP scripts.
Chapter 5, Using Databases and Transactions with JDBC and JTA, details how to connect to a data store and how to use transaction management with databases or other legacy data stores.
Chapter 6, Remote Method Invocation and Distributed Naming, discusses RMI and how to configure calls to RMI clients, including application clients and EJBs. It also discusses setting up the central registry of object names and locations with the JNDI.
Chapter 7, Enterprise Messaging with the Java Message Service (JMS), covers the fundamentals of JMS, describing and illustrating both point-to-point and publish-and-subscribe messaging. Topics include how JMS works in a WebLogic Server cluster, JMS exception handling, and best practices for using JMS in WebLogic Server applications.
Chapter 8, Using Session Enterprise JavaBeans, gives an overview of the very important EJB technology, which is the main mechanism for capturing business logic and managing interactions with data stores. This chapter covers stateless and stateful session beans, which provide services to clients. Like other J2EE objects, EJBs reside in the WebLogic Server container.
Chapter 9, Entity EJBs, describes how entity EJBs interact with data stores. EJBs provide several mechanisms for making data persistent in the context of the application. The WebLogic Server container handles security and transactioning for data managed by entity beans.
Chapter 10, Using Message-Driven EJBs, describes message-driven EJBs, which are the integration between EJB and the JMS. Like other EJB types, message-driven EJBs live within an EJB container and benefit from EJB container services such as transactions, security, and concurrency control. Message-driven EJBs do not interface directly with clients: They set a listener that receives messages from the interaction of the JMS provider with the EJB container.
Chapter 11, Interfacing with Internet Mail Using WebLogic Server JavaMail, discusses Internet mail (email) protocols, including the Simple Mail Transport Protocol (SMTP) and the POP3 and IMAP mail retrieval protocols. This chapter details the JavaMail API and shows how to add email capability to the WebAuction application.
Chapter 12, Developing Security with WebLogic Server JNDI and JAAS, surveys security technologies and shows you how to incorporate WebLogic Server security realms and Java Authentication and Authorization Service (JAAS) into your WebLogic Server applications. This chapter includes abundant details on how to create secure application clients and Web clients for WebLogic Server.
Chapter 13, Designing the Production Deployment, discusses scenarios for deployment of the production application. This chapter emphasizes the importance of planning ahead for deployment. Your deployment design choices are determined by the installation environments of servers and clients, and by the anticipated levels of use of the application. This chapter describes:
Typical WebLogic Server deployment scenarios
Sample deployment configurations for each scenario
Best practices for deploying WebLogic Server in the enterprise
Chapter 14, Packaging, Deploying, and Testing the WebAuction Application, discusses the architecture of the WebAuction application and how the various J2EE technologies were selected and employed. The chapter details how to package application components into an enterprise archive (.ear) file, and how to build and deploy the WebAuction application, step by step.The chapter concludes with a section on strategies for functional and performance testing of the completed application.
Chapter 15, Capacity Planning for the WebLogic Server, describes and illustrates a methodology and metrics for assessing the total capacity (user load, response times) of the WebAuction application. It includes:
Methodology and metrics for capacity planning
Examples that compare WebAuction to a hypothetical application, WebTrade
Capacity planning best practices