Appling Design Patterns And Application Framework To Develop Network Application Software

With the development at full speed of technology of the computer and network communication technology, network application software must be more flexible and efficient. Flexibility is needed to support a growing range of multimedia datatypes, traffic patterns, and end-to-end quality of service (QoS) requirements. Efficiency is needed to provide low latency to delay-sensitive applications and high performance to bandwidth-intensive applications over high-speed and mobile networks. But network application program continue to use traditional development mode still, thus cause development cost and maintain cost increase constantly but quality yet relatively low software. This situation has produced the so-called "distributed software crisis".In the solution to the problems mentioned above, object-oriented design mode and framework are one of the most flexible and strong tools. They contribute to reducing expensive rediscovering and reinventing key concept and abstract of network software, so it is paid attention to. Object-oriented techniques provide principles, methods, and tools that significantly reduce the complexity and cost of developing network application software. It is the primary benefits of object-oriented that it emphasizes the modularity, reusability, and extensibility of softwares. Design patterns are the reusable systematized solutions of some software development problems under specific background. They enable developers to reuse successful software designs and system architectures conveniently. Applications Frameworks are reusable software architectures that work for an entire family of related applications. A framework is a reusable, "semi-complete" application that can be specialized to produce custom applications. Design patterns and application frameworks can be applied together synergistically toimprove the quality of network application softwares by capturing successful software development strategies.The paper focus on how to use object-oriented design patterns and application frameworks reduce complexity and raise reuse in developing network application softwares. To illustrate it, this paper state how to design an accomplish a application proxy server. In this example, adaptive communication environment (ACE) and many kinds of design patterns are used. And this paper elaborations how to customize ACE framework and to use design patterns and application framework to promote the quality of the software.