外文翻译-----使用开放源码工具的专业便携式开发

Professional Portal Development with Open Source Tools

Design Pattern Considerations in Your PortalClearly, there are many ways to implement a design that cannot be expressed adequately in this chapteralone. Hopefully, the introduction of high-level pattern constructs and brief discussion of the implementationof Java standards in this chapter can facilitate your design decisions on your portal deployments.

Java language and implementation standards can also help control complexity so that consistent levels ofquality can be attained in your development activities. This in turn can lead to increased partner adoptionand portlet maintenance. Last, the adoption of design patterns should be applied so that best practices arepropagated in your portal deployment and development operations can be hastened.

Much has been written during the last few years about design patterns and their use in Java development,so rather than go into great elaboration of their use, we felt that it would be more beneficial to providehigh-level concepts of patterns that might be used in your portal deployments and to encourage you toexplore them from the online Javaworld newsletter and from the Core J2EE Patterns book [ALUR].

Planning for Portal Deployment

Using Java Standards

For many mission-critical development portal efforts, decisions need to be made about expensive softwareprocurements to satisfy your development needs. In order to protect this investment, it is wise toconsider standards when you make your purchasing decision because there is nothing worse thandumping a lot of money into a particular framework only to learn after you have obtained it that it is aclosed, proprietary system that does not work well with other systems. To guarantee that this does nothappen to you, you should become familiar with software standards and other application frameworks’use of them. Regrettably, systems that do rely heavily on proprietary extensions often force your projectto hire expensive expertise to help you deploy your program with their framework.

Figure 7.21 illustrates some of the Java standards that could be considered for portal development. It isimportant to remember that these need to be established prior to procuring a portal framework or integratingexisting applications into a homegrown portal application. Always be cognizant of the latest versionsof the standards listed in Figure 7.21, and the effects that newer versions of those standards mighthave on your design decisions.

Figure 7.21

Figure 7.22 illustrates some of the portal standards that should be considered before building your portalapplication.

On many portal implementations, a business case for adherence to language standards that relate toindividual portlets needs to be made so that proprietary extensions are not adopted by a program thatdisallows code reuse and promotes vendor lock-in. Being exposed to proprietary data formats, oneinevitably gets increasingly locked into the solutions of a particular vendor, which in turn limits theoptions for application software. This ultimately enables vendors to dictate enhancement prices andintroduces unnecessary risks to your system

Figure 7.22