Read an Excerpt
From Chapter 30: Oracle Application Server Web Toolkit Reference
... Browsers A browser is the end user tool for accessing the Web. It is the vehicle through which users interact with your application. Browsers understand HTML, and many even support Java, JavaScript, VB Script, VRML (Virtual Reality Modeling Language), and other languages. To test your application, you'll want a copy of all the browsers you plan to support. The two most popular browsers on the market today are Netscape's Navigator and Microsoft's Internet Explorer. Fortunately they are both free today. When testing your applications, it's important that you have a workstation running the "default system" so you can create a design checklist, which includes default fonts, colors, screen resolution, and so on, for your Web pages. Then you'll want to modify the settings, just as the users will, to see if your application breaks.
Add-Ins and Plug-Ins
Add-ins and plug-ins are programs that run on your workstation (PC) and typically use the network as a file transfer mechanism. If the program is integrated into the browser, it's called a plug-in. If the program is separate from the browser, it's called an add-in.
RealAudio (streaming audio), VRML players (virtual reality graphics players), and Cooltalk (Internet phone) are examples of plug-ins. The benefit of plug-ins is that they don't have to be downloaded each time you want to make use of their functionality. Plug-ins are options that may enhance your site's look and feel. Your Web applications don't have to use plug-ins; in fact, many sites are "plug-in free," which meansthey don't require plug-ins.
Pointcast, on the other hand, is an example of an add-in. Pointcast is a separate executable that runs on your PC. Pointcast uses the Web to download its data such as news, stock quotes, magazines, newspapers, and other media information.
Add-ins and plug-ins have their place, but most of them will probably be replaced by options that run in a standard browser using Java, JavaScript, or other solutions that don't require that users download and install software on their local workstations. If you decide to use add-ins or plug-ins for your site, you need to consider how appropriate it will be for your end users to download, install, use, or upgrade an add-in or a plug-in.
The Oracle Suite of Tools
Oracle's suite of tools gives you everything you need to design and develop scalable applications that run on a powerful and robust database engine. Oracle Application Server, in particular, provides a solid back-end server for traditional Web page and site development. Its strength lies in its ability to run with an Oracle database and its ability to transparently use PL/SQL. This strength, along with its Designer/2000 and Developer/2000 toolkit, make the Oracle Application Server the best choice for today's Web application developer interested in creating true cross-platform applications.
From objects that encapsulate data to relational databases that allow the storage and retrieval of data, the Oracle Application Server does it all. How? By drawing on the same concepts that make the Internet so successful. Oracle's Application Server provides the scalability, compatibility, and security demanded by today's application developer.
The Evolution of Oracle's Web Server
From its beginnings, Oracle's Web server products have lead the industry with technological breakthroughs designed to meet market demands.
Oracle WebServer Version 1.0
Late in 1995 Oracle released version 1.0 which came with a Web Listener and a CGI Interpreter Web Agent. It allowed users to execute CGI modules, and since PL/SQL was a CGI (there were no cartridges), each database request was treated as a new process on the system.
Oracle WebServer Version 2.0 and 2.1
When WebServer version 2.0 was released, Oracle got the attention of users around the world. This was definitely a highly functional application development tool. It came with a Web Listener, a Web Request Broker, Interpreter cartridges, an extended PL/SQL Web Toolkit, and much more. Version 2.0 allowed for the execution of CGI modules, PL/SQL modules, and server-based Java modules, among others. It also supported customization.
In WebServer version 2.0 and 2.1, three cartridges were added: the PL/SQL, Java, and LiveHTML cartridges. The PL/SQL cartridge replaced the CGI module in the earlier version. Cartridges have many advantages over CGI modules. Most notably, cartridges are persistent (stay running in memory), while a CGI module is not persistent. As a result, every time a CGI module is called, it must be reloaded and run—a much slower process.
Version 2.1 also offered the support of competitive Web Listeners. This allowed companies to use other Web Listeners, such as Microsoft IIS, to communicate with Oracle's Web Agents.
Oracle Web Server Version 3.0, Web Application Server
Version 3.0 moved Oracle's Web server to an open architecture. It was so different from the prior versions, Oracle even renamed it from Oracle WebServer to Oracle Web Application Server. This version supports CORBA (Common Object Request Broker Architecture), which is an industry standard protocol supported by a wide variety of hardware and software vendors, and also includes:
- Web Request Broker enhancements
- A dispatcher for load balancing
- APIs (request services routines, inter-cartridge communication routines, transaction service routines, content management routines, and persistent storage services)
- Authentication services cartridges
- Java cartridge
- PL/SQL cartridge
- LiveHTML cartridge
- ODBC cartridge
- Perl cartridge