This is the first in a series of articles that looks at how a relatively simple Java servlet application can provide a useful multi-channel service, accessible to both mobile wireless and desktop clients. The application we'll develop is a real estate service providing access to homes and other properties. Real estate agents can use this service while they're on the road, at home, showing properties to their clients, or in the office. Our example uses WAP's Wireless Markup Language (WML) for the wireless web channel, although we could easily substitute another XML-compliant markup language such as XHTML.
These articles show you a process that can help you build a flexible wireless web application. They also explain how to use XML and XSLT to define a template-driven user interface, and explore some of the common problems in wireless application development.
The process begins with an opportunity assessment so we can determine whether our application makes sense in a mobile world. We check for the following characteristics:
User workflow can be broken into a series of simple steps.
Minimal text entry is required.
The application takes advantage of time, location, and/or personalization.
The application has a sustainable business model (someone will pay for the application).
The application satisfies a genuine user need—what Paul May, in his book Mobile Commerce: Opportunities, Applications, and Technologies of Wireless Business (Cambridge University Press, 2001), refers to as a user's mission.
The Real Estate Assistant application is appropriate for the mobile world because it satisfies these requirements, as shown below:
User workflow can be broken into a series of simple steps. The workflow is a simple sequence of query, summary, and details.
Minimal text entry is required. The application uses drop-down lists to choose price range and property type.
The application takes advantage of time, location, and/or personalization. The application takes advantage of location (information is available to agents when they're on the move or showing properties) and time (new properties are immediately available).
The application has a sustainable business model (someone will pay for it). Real estate offices will pay for the service by subscription.
The application satisfies a genuine user need. The application is genuinely useful because it lets agents access up-to-date property information from any location and at any time. It enables them to accomplish their mission of locating and selling appropriate properties to their clients.