The xml litmus test understanding when and why to use xml

Introduction

As the popularity of XML has grown, its usage has spread to every nook and cranny of software application development. This is due to the fact that, unlike previous data formats, XML can easily represent both rigid, highly structured data (such as relational data from a database, program configuration files, or spreadsheets) and semi-structured data (such as a Web page or business document). Besides being able to represent both structured and semi-structured data, XML has a number of characteristics that have caused it to be widely adopted as a data representation format. XML is extensible, platform-independent, and supports internationalization by being fully Unicode compliant. The fact that XML is a text-based format means that when the need arises, one can read and edit XML ...........................

This popularity has meant that in certain cases XML is chosen as a data representation format when it is not the best tool for the job. This article provides a clear set of guidelines for determining when XML is the right choice as a data representation for a particular Situation. Additionally, Some Examples of Appropriate and INAPPRIKEES OF XML Are Described.

The XML Litmus Test

In my article Understanding XML I described some of the benefits of using XML as a data representation format. Due to widespread support for XML across various software platforms, the primary benefit of using XML is that it is easier to interoperate between applications on different platforms using XML than with most other data representation formats. The second major benefit of using XML is a side effect of its popularity. There are a large number of off-the-shelf tools for dealing with XML including parsers, schema languages, query languages, programming models, editors, and much more. No other data representation format has such a wide array of tools for processing instances of the format on so many platforms.The aforementioned benefits give us the XML Litmus Test. XML is the appropriate tool for the job if The Following Criteria Are Satisfied by Choosing XML As The Data Reperestation Format for a Given Application:

There is a need to interoperate across multiple software platforms. One or more of the off-the-shelf tools for dealing with XML can be leveraged when producing or consuming the data. Parsing performance is not critical. The content is not primarily binary content, Such as a music or image file. The Content Does Not Contain Control Characters That Aren't Carriage Return, Line Feed, or Tab Because They Are Illegal in XML.

If The Expected Usage Scenario Does Not Satisfy at Least Four of the Above Criteria, The IT MAY NOT Make Much Sense To Use Xml As The Data Reperestation Format for the Situation In Question.

Even when the usage of XML satisfies the criteria, there are still trade-offs that need to be considered. For example, because XML is a text based format and uses redundant tags for labeling content, there are often complaints about the bloat caused by choosing XML as a data representation format. However, in cases where XML brings the benefit of interoperability and a wide array of technologies for describing and processing the data, then this trade off is worth it. This is exactly the trade off in using XML as the basis for network protocols such as XMPP and SOAP.Using XML as an application configuration file format is another area where a trade-off has to be considered as well. On the surface, XML seems more complex than is needed for most application configuration file needs In Most Cases this is true. Honefits to the table. These benefits include Internationalization, BUILT IN MECHANISMS for Creating Comments and escaping text, and widely deployed tools for consuming and producing XML. It is often the case that the cost of writing a parser for a custom configuration file format, as well as other tools, outweighs any benefits from the formats simplicity over XML. Considering this trade off, XML is usually , But Not Always, The Right Tool for the Job When COMING UP WITH Application Configuration Files.

The Rest of this article applies the xml litmus test to a number of established uses of xml.

Some appriate Uses of XML

XML was originally intended as a language for defining new document formats for the World Wide Web. XML is derived from the Standard Generalized Markup Language (SGML), and can be considered to be a meta-language, a language for defining markup languages. The benefits of using XML on the Web are self-apparent. On a widespread global network such as the World Wide Web, interoperability across platforms is key, as is the fact that it fully supports internationalization by being Unicode compliant.One popular usage of XML on The Web Today Is for XML Syndication Feeds Such AS RSS 1.0 or RSS 2.0. Below Is A Sample RSS 2.0 feed.