The World Wide Web is more and more used for application to application communication. The programmatic interfaces made available are referred to as Web services. The goal of the Web Services Activity is to develop a set of technologies in order to lead Web services to their full potential. The Web Services Activity Statement explains the W3C's work on this topic in more detail.
Web Services Addressing 1.0 - Core (WS-Addressing) defines two constructs, message addressing properties and endpoint references, that normalize the information typically provided by transport protocols and messaging systems in a way that is independent of any particular transport or messaging system. A Web service endpoint is a (referenceable) entity, processor, or resource to which Web service messages can be addressed. Endpoint references convey the information needed to address a Web service endpoint. This specification defines a family of message addressing properties that convey end-to-end message characteristics including references for source and destination endpoints and message identity that allows uniform addressing of messages independent of the underlying transport.
Services Description Language:
As communications protocols and message formats are standardized in the web community, it becomes increasingly possible and important to be able to describe the communications in some structured way. WSDL addresses this need by defining an XML grammar for describing network services as collections of communication endpoints capable of exchanging messages. WSDL service definitions provide documentation for distributed systems and serve as a recipe for automating the details involved in applications communication. A WSDL document defines services as collections of network endpoints, or ports. In WSDL, the abstract definition of endpoints and messages is separated from their concrete network deployment or data format bindings.
The Java Web Services Developer Pack (Java WSDP) is a free integrated toolkit you can use to build, test and deploy XML applications, Web services, and Web applications with the latest Web service technologies and standards implementations. With the newest release of the Java WSDP 2.0, developers will be able to:
Develop and deploy using the latest XML and Web services technologies slated for inclusion into Sun's deployment platforms.
Enhance Web services performance without revising WSDL files or application code with the refreshed Fast Infoset features from Java WSDP 1.6.
Create XML and Web service-enabled applications that exploit the enhanced security features with enhanced XWSS features.
Continue to enjoy Java interoperability and portability across different platforms and devices.
Simplify and lower the cost of legacy application integration, data interchange, and publishing in a Web environment.
In this article, we have tried to keep a realistic, pragmatic, and balanced approach in determining the return on investment on Web Services. It is worth mentioning that, no matter how promising a new technology is, promoting and encouraging its usage through such articles and papers is not justified until there is a solid business case for its adoption. It is fundamentally important for us to warn about the pitfalls as and where we foresee them, leaving the final decision up to the readers who range from senior management (technical and business), through business analysts, and systems architects, to project managers, and software developers.
Looking back over the last six years, it is hard to imagine networked computing without the Web. The reason why the Web succeeded where earlier hypertext schemes failed can be traced to a couple of basic factors: simplicity and ubiquity. From a service provider's (e.g. an e-shop) point of view, if they can set up a web site they can join the global community. From a client's point of view, if you can type, you can access services. From a service API point of view, the majority of the web's work is done by 3 methods (GET, POST, and PUT) and a simple markup language. The web services movement is about the fact that the advantages of the Web as a platform apply not only to information but to services.
Apache Axis is an implementation of the SOAP ("Simple Object Access Protocol") submission to W3C.
From the draft W3C specification:
SOAP is a lightweight protocol for exchanging structured information in a decentralized, distributed environment. It is an XML based protocol that consists of three parts: an envelope that defines a framework for describing what is in a message and how to process it, a set of encoding rules for expressing instances of application-defined data types, and a convention for representing remote procedure calls and responses.
This project is a follow-on to the Apache SOAP project.
Please see the Reference Library for a list of technical resources that should prove useful.
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