Web application portals cater to various types of concurrent users and requests. The number of requests varies by time of day and day of week. Despite the variation in workload, it is important to provide the expected performance (response time) to users of these applications. To assure an appropriate level of performance, web application portals should be analyzed and evaluated throughout their software development lifecycles. Model Driven Architecture (MDA) provides a structured process for developing and analyzing web application portals from the requirement analysis to the ultimate deployment. This chapter examines recent advances in performance analysis methods for web application portals and shows how they can be integrated with MDA methods to analyze performance analysis throughout their software development lifecycles.
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Emerging trends and challenges. The advent of web-based applications, such as shopping, social networking, photos, videos, music, gaming, and chat, are increasing the popularity and accessibility of the Internet. There is also growing focus on application integration platforms, such as Sun’s Java Composite Application Platform Suite, Facebook’s Application Platform, and Oracle’s Application Development Framework, where a single portal can provide many services. These integrated web sites are referred in this paper as web application portals, which are Internet sites that provide multiple services to users. For example, users of social networking sites, such as Facebook (www.myspace.com), upload recent photos and videos, exchange messages and chat with each other, and play online games with friends.
Figure 1 shows the architecture of a typical web application portal, such as www.hotwire.com, that help users build vacation packages with choices for flights, hotels, rental cars, and cruises. Users submit requests to the portal, which in turn contacts various service providers for each service and forwards responses to users. Web application portals should be scalable to support a variety of services and the large number of customers accessing the services simultaneously. The scalability requirements for these sites typically grow as the number of service providers increases.
Figure 1. A travel site that provides interface to hotels, flights, rental cars, and cruises
Competition between providers of web application portals is also growing. Providers have different marketing differentiators and focus on different features and services. For example, IMDb (www.orbitz.com), aim to provide the best travel deals to customers within a reasonable time frame, which may vary from person-to-person and from application-to-application. In particular, user submitting travel queries may be willing to wait longer for the best deals than users searching for a phone number. Given the proliferation of web-based application portals in the Internet, users who are not satisfied with one provider can often switch to alternative providers, which incentivizes providers to enhance the QoS of their web application portals.