Directions for J2EE Patterns

There are a number of patterns that have been identified as recurring in J2EE design and development. However, the list of J2EE patterns provided earlier is not a definitive and final one. More J2EE-specific patterns will undoubtedly emerge over time due to various factors:

• Because more applications are developed based on existing J2EE technologies, more patterns may be mined by identifying other common design elements within those applications.

• New patterns will evolve based on newly released technologies that become part of the J2EE platform.

• New applications of all these technologies will lead to new requirements. The solutions to these new requirements will give rise to new patterns of use and, hence, to new J2EE patterns.

Another aspect of the emergence of patterns in environments such as J2EE is that the common patterns become embodied in the environment itself. This was noted earlier where patterns such as Proxy are prevalent in the infrastructure and generated classes of a J2EE application. As J2EE evolves, more patterns will be captured in the underlying platform. An example of this is the introduction of servlet filters in J2EE 1.3, which embodies much of the Intercepting Filter pattern.