Servicing The Web

Sun Microsystems recently released a set of interfaces and applications that should simplify the creation of Web services. The Web Services Pack includes JAX Pack APIs, JavaServer Faces, and Tomcat. The software, only part of which is available now, is being developed through Sun's Java Community Process, which includes about 350 Java developers.

The Web Services Pack is due to become part of the Java 2 Enterprise Edition. Borland, Oracle, WebGain, and Sun's Forte division plan to support the technology in upcoming products. The APIs are likely to be included in integrated development environments, application and integration servers, and packaged applications.

JAX Pack consists of five APIs, all designed to create smoother links between Java and XML, the two underlying technologies that are fueling Web services. JAX Pack includes:

For companies that are developing Web services to collaborate with business partners, JAX Pack offers a faster way to develop applications while maintaining independence from any particular vendor's XML technologies.

Of the five Java APIs in JAX Pack, only one--the Java API for XML Processing (JAXP)--is completed. JAXP gives developers flexibility by letting them easily swap out XML parsers. They may want to do that if a parser that performs better for their application becomes available. Without the use of JAXP, it's easy for programmers to lock themselves into one vendor's XML parser.

"The Java API for XML Processing is very useful for building Web services," says Ed Rowan, CEO of the Middleware Co., an Austin, Texas, training and consulting company focused on server-side Java development.

The other four APIs in the JAX Pack are still in development and are due to be released by year's end.

The Java Architecture for XML Binding (JAXB) is an API and toolset for creating two-way mapping between XML documents and Java objects. JAXB makes it easy for a developer to take a description of an XML language--for example, the XML schema for Chemical Markup Language, which is used by the chemical industry to exchange molecular information--and create a set of Java classes that process data encoded in the Chemical Markup Language. Without JAXB, programmers have to write Java code to format the parsed XML data into Java objects according to the XML schema. Such coding is tedious to write and usually isn't portable.

For 724 Solutions Inc., a Toronto wireless infrastructure and solutions provider that uses Java for back-end server operations, JAXP and JAXB will speed the development of wireless solutions for customers, says Mark Hopkins, the company's technical director.

ClearCommerce Corp., an E-commerce software company in Austin, Texas, uses JAXP and the Sun XML parser that's included in Sun's JAXP reference implementation to handle the XML document flow between storefronts and the ClearCommerce Engine. "Using the parser and transformer in JAXP makes it easy to take ebXML E-business XML standard and OFX Open Financial Exchange output and transform it to our own Document Type Definition format," says Bill Podell, ClearCommerce's technical services director.

The Java API for Messaging is designed to allow easy access to emerging XML messaging standards, such as ebXML Transport/Packaging and Routing. It typically will be used along with JAX-RPC--the Java API for XML-based remote procedure calls--which will give Java programmers a single interface to any XML-based RPC mechanism, including the Simple Object Access Protocol standard.

Although Soap is the acknowledged XML transport standard for Web services, developers using JAX-RPC will be better able to switch to any future XML-based RPC mechanism. Although ClearCommerce hasn't deployed Java API for XML Messaging (JAXM) and JAX-RPC, it's considering using them in future versions of its products. "We'll use JAXM and JAX-RPC as a way to take messages off our engine and move them to third-party applications to request a response," Podell says.

Other developers are moving ahead with Web services projects despite the prospect of future code rewrites when various JAX Pack APIs are released. These developers have had to develop custom code for the connections between Web services.

Fuegotech Inc. is a provider of business-process-management software whose main product, FuegoBPM, uses JAXP as the basis for communication between different technologies, including Corba and Microsoft's Component Object Model. The company has had to create its own version of JAX-RPC using the Soap standard as a starting point. However, Fuegotech expects few difficulties moving to JAX-RPC when the specification is available. "The effort should be minimal because we're already Soap-compliant," says Emilio Lopez-Gabeiras, chief technical officer of the Addison, Texas, company.

The Java API for Registries will be a uniform, standard interface to registries of XML business data such as the Universal Description, Discovery, and Integration protocol. It will help Java developers design portable E-business applications that can register and extract data from various registries, including those used with the ebXML modular business framework for global E-commerce, sponsored by the United Nations and the Oasis standards organization.

The two applications that are part of the Web Services Pack are JavaServer Faces and Tomcat. JavaServer Faces is an API for building Web graphical user interfaces. It eliminates the need for developers to create and maintain the interfaces from scratch.

Tomcat is an open-source implementation of JavaServer Pages and Servlet technologies that developers can use as a starting point for building Web services. JavaServer Pages separate content and display data in an application, which makes it easy for developers to swap out different pieces of code without having to rewrite the entire application. Servlets provide a consistent way for Java applications to access other business systems.

The various interfaces and applications will be posted for free on Sun's Web site as they become available. When all are completed, the Web Services Pack will be rolled out in a single download.