XML in a Nutshell, 3rd Edition

Mixed Environments

Modern enterprise applications often involve software running on different computer platforms with a variety of operating systems. Choosing a communication protocol involves finding the lowest common denominator available on each system. Thanks to the enormous number of XML parsers that can be freely integrated with applications in a wide variety of environments, XML has become a popular format for data sharing.

Imagine an application server that needs to display data from a mainframe to users connected to a corporate web site. In this case, XML acts as the “glue” to connect the web server with a legacy application on a mainframe. The web server can send an XML request to the application server. The application server converts the request to what the legacy server expects and calls the legacy application. In the reverse direction, the application server converts the legacy server’s response to XML before passing it back to the web server. Using a technology like XSLT, the web server can then transform the XML into a number of acceptable web formats for distribution to clients. By adopting XML as the common language of your enterprise, it becomes easier to reuse existing data in new ways.

Even on smaller systems, XML can be useful for sharing information between applications written in different languages or running in different environments. If a Perl program and a Java program need to communicate, generating and processing XML can be simpler than creating a custom ...