Special Edition Using Java™ 2 Enterprise Edition

Three-Tiered Applications

A three-tiered design is the most flexible and the most complicated to build. By separating presentation, business logic, and data layers into their own components, you can change the implementation of each layer without affecting the other layers. Figure 1.4 shows the structure of a typical three-tiered application.

Figure 1.4. A three-tiered application has separate presentation, business logic, and data components.

When you separate the presentation, business logic, and data layers, you must determine how the layers interface with each other. The interface between the business logic and data layers is often determined ...