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Will Web services jump-start the software slump?

Industry leaders make their predictions -- and investments

By John Rommel, JavaWorld.com, 08/31/01

Web services are software applications that allow their programs to run over the Internet -- taking advantage of new technology standards and creating workable and efficient e-commerce transaction-processing systems, among other applications. These software components network with other Web services dynamically, and use existing Internet technologies to create links between systems without massive re-engineering. A Web service is a compilation of responsibilities summarized into a stand-alone object, which users can access from the network. In a nutshell, Web services link, locate, and speak to other entities outside your own Web services system by spanning every linked Internet application.

New technologies driving the paradigm

To drive this new Web model forward, Java developers must familiarize themselves with the new technology standards derived from XML:

• Simple Object Access Protocol (SOAP), known as XML Protocol messaging specifications, is a standard for reliably transferring application triggers between Internet applications.
• Universal Description Discovery and Integration (UDDI) enables applications to broadcast specifications on how they want to manage information exchange with other applications. Those applications also hunt for information-trading partners to provide goods and services they need by querying UDDI registries (an open framework for relating and integrating application services, plus an operational registry).
• Web Services Description Language (WSDL) is an XML format for connecting network services as endpoint sets operating on messages that are either procedure- or document information-oriented. WSDL describes which programs are accessible via communication query by any network with message formats and protocols. WSDL is valuable because it provides for a programming standard and enables Web services to describe their capabilities, permitting easier interoperability among Web services and development tools.

These standards allow for core application assembly, taking the place of Enterprise JavaBeans (EJB) and other major vendors' competing standards. Chief industry players, including Hewlett-Packard, IBM, Microsoft, and Sun, are currently working to strengthen Web services technology and standards like SOAP and WSDL. Vendor toolkits allow pre-existing JavaBeans to easily adapt to Web services. The Java 2 Platform, Enterprise Edition (J2EE) lets you write the fundamental parts of business applications (for example, connections to databases, transaction handling, and so forth) that will run across different computing systems. Web services for servers will be included in a future J2EE release.

Web service example

To better understand how Web services work, imagine the sort of Web service the real estate industry might offer. A consumer employs a Broker service, which searches a UDDI directory to identify several lenders. Those lenders all correspond to a unique dialect of XML schema (XML schema is a diagram or template that provides a road map to access data from linked systems). The Broker service's business logic then corresponds with preferential lenders, allowing the business service program logic to assess mortgage proposals from multiple lenders and provide advice to the client, based on the XML returned to the Broker. The Broker could also arrange other supporting services such as Escrow, Inspection, Insurance, and an Appraisal service, given that this data conforms to a consistent schema.

 

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