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Overview of JAXR

This section provides a brief overview of JAXR. It covers the following topics:

What Is a Registry?

An XML registry is an infrastructure that enables the building, deployment, and discovery of Web services. It is a neutral third party that facilitates dynamic and loosely coupled business-to-business (B2B) interactions. A registry is available to organizations as a shared resource, often in the form of a Web-based service.

Currently there are a variety of specifications for XML registries. These include

A registry provider is an implementation of a business registry that conforms to a specification for XML registries.

What Is JAXR?

JAXR enables Java software programmers to use a single, easy-to-use abstraction API to access a variety of XML registries. A unified JAXR information model describes content and metadata within XML registries.

JAXR gives developers the ability to write registry client programs that are portable across various target registries. JAXR also enables value-added capabilities beyond those of the underlying registries.

The current version of the JAXR specification includes detailed bindings between the JAXR information model and both the ebXML Registry and the UDDI version 2 specifications. You can find the latest version of the specification at

http://java.sun.com/xml/downloads/jaxr.html 

At this release of the J2EE platform, JAXR implements the level 0 capability profile defined by the JAXR specification. This level allows access to both UDDI and ebXML registries at a basic level. At this release, JAXR supports access only to UDDI version 2 registries.

Currently several public UDDI version 2 registries exist.

The Java Web Services Developer Pack (Java WSDP) Registry Server provides a UDDI version 2 registry that you can use to test your JAXR applications in a private environment. You can download the Java WSDP from http://java.sun.com/webservices/downloads/. The Registry Server includes a database based on the native XML database Xindice, which is part of the Apache XML project. This database provides the repository for registry data. The Registry Server does not support messages defined in the UDDI Version 2.0 Replication Specification.


Note: If you use the Java WSDP Registry Server to test JAXR applications that you develop using the Sun Java System Application Server Platform Edition 8, make sure that in your PATH you place the Application Server bin directories before the Java WSDP bin directories.


Several ebXML registries are under development, and one is available at the Center for E-Commerce Infrastructure Development (CECID), Department of Computer Science Information Systems, The University of Hong Kong (HKU). For information, see http://www.cecid.hku.hk/Release/PR09APR2002.html.

A JAXR provider for ebXML registries is available in open source at http://ebxmlrr.sourceforge.net.

JAXR Architecture

The high-level architecture of JAXR consists of the following parts:

A JAXR provider implements two main packages:

The most basic interfaces in the javax.xml.registry package are

The primary interfaces, also part of the javax.xml.registry package, are

When an error occurs, JAXR API methods throw a JAXRException or one of its subclasses.

Many methods in the JAXR API use a Collection object as an argument or a returned value. Using a Collection object allows operations on several registry objects at a time.

Figure 10-1 illustrates the architecture of JAXR. In the Application Server, a JAXR client uses the capability level 0 interfaces of the JAXR API to access the JAXR provider. The JAXR provider in turn accesses a registry. The Application Server supplies a JAXR provider for UDDI registries.

JAXR Architecture

Figure 10-1 JAXR Architecture

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