Part 2 of this series followed a real estate agent using the mobile (WAP) interface to the Real Estate Assistant service. We examined the core Java source code, XSL user interface templates, and XML test data file. This article continues our code-level walkthrough, this time in the context of a web browser interface, and discusses the challenges faced in building this service. These challenges include the multichannel user interface and limitations inherent in mobile devices. We then move on to testing and conclude with a look at deployment issues and future work.
Beginning where we left off, let's look at how a real estate agent would interact with the Real Estate Assistant via a web browser. Workflow for the wireless and web interfaces is similar; the primary difference is that query entry easily fits on a single browser screen, where the mobile browser splits the inputs into a sequence of three windows.
The HTML query style sheet is shown in Listing 3-1 (click here to download the listing files for this article). As in the WML style sheet, a single root template produces a complete page. Drop-down lists allow the agent to choose the minimum and maximum price and the type of property. New to this template is an additional text field that lets the agent choose how many results to display on each page. Figure 1 shows a browser query in progress.
Figure 1 Web query form.
The query is processed in pretty much the same way as the wireless query, with the following differences:
The user-specified results-per-page value is used in place of a default.
The HTML viewer is used in place of the WML viewer to display the results.
The HTML viewer selects an HTML-generating results style sheet (listed in Listing 3-2 in the listing files for this article). Like the WML-generating style sheet discussed previously, this style sheet produces either a message to the effect that no results were found, or a list of matching properties. This time, however, there is no need for a summary listing from which details are requested; the complete property details are generated in a series of four column tables as shown in Figure 2.
Figure 2 Web results page (partial).
Note that some additional information (such as dimensions) is available on the web version of this service, and it would be possible to add images and further data in the production version.