Java is no longer the hottest technology. Extensible Markup Language (XML) has stolen the limelight. I guarantee that any computer magazine you see will at least mention XML. The curious thing is that, although XML is a very new technology, a wide variety of software is already available for it. The problem with this rampant emergence of XML software is that XML standards havent had enough time to evolve. And, once again, industry giants IBM and Microsoft are fighting to have their own XML standard adopted.
XML is, like HTML, a tag-based language, but unlike HTML, XML is extensible, making it easy to extend in the development of your own industry-specific markup language. The benefits of XML are its readability and simplicityfinally, a new technology that is easy to learn and deploy! XML has four general uses. First, as meta content, XML is used to describe meta information of other documents or online resources. Second, as rich document descriptions, XML is used to customize and enrich document descriptions. Third, as mini databases, XML is used for publishing and exchanging database contents. And fourth, XML is used as a messaging format for communication between application programs. XML is clearly poised to be the standard messaging framework for business-to- business applications.
Whos Doing XML?
Various industry groups have quickly seen the potential for XML and are developing their own industry-specific XML languages. The international electronic data interchange (EDI) community, for instance, developed XML/EDI. EDI has been around for years, but because of its complexity, few companies have been using it. XML/EDI was designed to make EDI simple. Lotus Domino now has DataChannel RIO, a technology that uses XML to integrate Lotus databases with other applications. IBMs Java Toolbox for the AS/400 now uses two XML languages, Program Call Markup Language (PCML) and Panel Definition Markup Language (PDML), to simplify calling AS/400 programs and designing Java GUI applications. Enterprise resource planning (ERP) software maker SAP plans to integrate XML into its business application programming interfaces, giving developers access to the internal workings of the companys R/3 software. Even the sky isnt the limit
for XML because NASA plans to use XML to develop an instrument control language for infrared devices on satellites and space telescopes.
The latest and greatest technologies always have big conference events, such as Java One and Internet World. You might not think that XML (merely a simple markup language) would merit a conference, but apparently, XML is worthy. SIGS Publications and Conferences held XML One on May 24, and InterDoc will host XML World on September 13, 1999, in Ottawa, Ontario, Canada (www.interdoc.ca/ conference/xml/index.htm).
Using XML Today
The biggest problem with XML is generating the XML content, delivering it, and then presenting that content. XML describes the structure but not the presentation of data. Yet another markup language, Extensible Style Language (XSL), has been proposed as a method of describing the presentation of XML content. The problem with XSL is that there is no standard for it yet. Naturally, Microsoft and IBM are fighting to have their own implementations of XSL ratified by the World Wide Web Consortium as the XSL standard. But you dont have to wait for XSL ratification; Internet Explorer 5.0 supports Microsofts version of XSL (although some say that Microsoft is trying to pollute XML the same way it polluted Java in its continual effort to promote Microsoft operating systems). IBMs version of XSL is LotusXSL, a Java-based XSL processor, available for free download at IBMs alphaWorks site www.alphaworks.ibm.com. Another alternative for presenting XML data is to develop a Java API that is customized for your industry-specific XML. Java and XML work well together; you could say that Java is to XML what RPG is to DDS.
To generate XML content, you can easily develop programs using any variety of languages to convert DB2/400 data into an industry-specific XML language. You can also use Message Oriented Middleware (MOM), such as IBMs MQSeries, to deliver that content. But a growing number of products generate and deliver XML content, such as Bluestones XML Suite (www.bluestone.com), Microsofts BizTalk server, and webMethods B2B server (www.webmethods.com).
Another XML product worth mentioning (because its free) is IBMs XML Enabler, available for download from IBMs alphaWorks site. XML Enabler allows you to convert XML-tagged data into HTML based on the style specifications of an associated XSL document. The XML Enabler is implemented as a server application (its actually a Java servlet). When a user requests an XML document, the Enabler uses the alphaWorks LotusXSL processor and the XML Java Parser to dynamically convert the XML document into HTML following the style specified in an XSL document.
We can wait for industry standards for XML and XSL, we can choose to use Microsoft or IBM XML strategies, or we can develop our own XML languages and our own Java APIs to present the content of our industry-specific XML. For further information on XML standards, visit the Web sites of the following nonprofit organizations: OASIS, the Organization for the Advancement of Structured Information Standards (www.oasisopen.org), RosettaNet (www.rosettanet.org), and the World Wide Web Consortium (www.w3c.org).