The Client Tier

The client tier is the "face" that you associate with Crystal Enterprise. A particular end user might think of the Web Desktop application page that shows up in her Web browser as Crystal Enterprise. However, Crystal Enterprise has many faces, each distinct and useful. By adopting a flexible approach toward potential client applications, Crystal Enterprise offers a system architect diverse means of sharing information with diverse audiences: an executive receives a text message on his cellular phone with the latest profitability statistics; a shipping clerk receives an order on the workgroup printer; a supplier company receives an XML file with detailed order specifications. These are but a few faces of Crystal Enterprise.

To begin categorizing the client tier, define three groups of audiences that will use client applications: the end user, content creator, and administrator. Although these groups are not mutually exclusive (a particular person can have all three roles), this distinction helps to explore important dimensions of each.

End-User Clients

The most common end-user client for Crystal Enterprise is a Web browser. Many of the client applications that are included with Crystal Enterprise, such as the Web Desktop, use a Web browser as their client. Additionally, most custom application development targets the Web browser.

With the proliferation, adoption, and maturation of the Internet as a communications medium, additional client tools offer diverse venues for end-user experiences. Internet-connected phones and mobile devices already grace the belts and briefcases of the more tech-savvy.

With each client targeted for an end-user community, specific considerations take the fore. For instance, most Internet-connected phones have small screensthey can only display a few lines of text at a time. Because Crystal Enterprise is so widely experienced within the Web browser, several browser-related considerations merit your attention. Web browsers such as Internet Explorer and Netscape or Mozilla are page-oriented: They display one page at a time. Users expect these pages quickly and become frustrated at what they consider long waiting times for pages to display. The benchmark hovers at between 5 to 10 seconds for the patience of a typical Web user.

The Web experience also is by and large a simple one. You see a blue-underlined word, and know that you can click on it to go somewhere. Originally, Web browsers were simple text display programs. The capability of today's browsers to render complex graphics and reflect exact positioning represents a tremendous maturation of the technology, but you must remember that a Web browser was not initially designed for this, and even today limitations, most notably around printing, reflect these origins. For content such as Crystal Reports, where pixel-level formatting is vital, and for content such as Crystal Analysis Workbooks, where interactivity is vital, Crystal Enterprise provides special facility for overcoming the limitations of the Web browser.

The Crystal Enterprise report viewers were presented in Chapters 22, "Introduction to Crystal Enterprise," and 23, "Using Crystal Enterprise with Web Desktop." For each type of object managed in Crystal Enterprise, there are specific viewers made available. These viewers appear in the browser and include buttons for exporting, printing, navigating, searching, and so on. These viewers provide pixel-level positioning, tremendous interactivity, and graphical capability. Crystal Enterprise 9 implemented a new viewing architecture, now improved and deepened in version 10. The viewer object in the CE-SDK renders reports and provides a simple interface for the Web developer to embed a Crystal Report or Crystal Analysis Workbook. The developer sets the properties of the viewer to determine the capabilities an end user has. For instance, the report export capability might be inappropriate for a certain end-user population, and so can be turned off by setting the HasExportButton property to 0.

The Web browser receives only DHTML and images, with the exception of the optional print control. Should a user choose to print a report, either an ActiveX print control or an Adobe Acrobat file is used to print while maintaining pixel-level formatting and fidelity.

In earlier versions of Crystal Enterprise, reports were rendered via a URL request to the viewrpt.cwr page, which was processed by the Web Component Service provided by Crystal Enterprise. The new control enables a developer to embed a viewer control wherever they want in a Web page, to be platform independent, and to fully secure and control the report viewing experience.

Crystal Enterprise supports the following browsers:

Content Creation Applications

Applications, such as Crystal Reports or Crystal Analysis, install on the report developer's machine and create and publish content to the Crystal Enterprise Framework. These were introduced and covered extensively in Parts I through IV.

Administrative Client Applications

Applications such as the Crystal Management Console (CMC) allow administrative users to manage the Crystal Enterprise system. Administrators might also use the Crystal Configuration Manager (CCM) for server-level management. The CMC is a Web-based application, but the CCM is an installed application. Coverage of these administration tools is provided in Chapter 27, "Administering and Configuring Crystal Enterprise."

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