Why Use Three-Tier and Components?

The most commonly used application development architecture, and the one supported by most application servers, is a component-based, three-tier model. Components increase code reuse and simplify development, and three-tier development increases scalability and reliability by isolating the three main logical functions of an application (user interaction, business logic, data storage) from one another.

Neither component-based programming nor the three-tier model is entirely new. Instead, both reflect the current thinking of how to achieve two longstanding goals: write less code, and make the code that is written easier to deploy, scale, maintain, and enhance.

Why Components?

A developer maxim states: “the best line of code is the one you never had to write.” This accurately reflects the reality that every new line of code written (or existing line of code that is modified) by a developer is a potential bug. Reusing code reduces the amount of new code that must be written, thereby allowing developers to build applications with fewer bugs and in less time.