The use of the term "Web" implies that web services are based on the World Wide Web. Web services, however, are not limited to the Web itself. Web services are a new approach for building, extending, integrating and deploying applications based on XML. This new approach builds applications that can facilitate the communication process over the Internet, as well as the communication process between applications.
Web services are software components that impact application structures. They help the interoperability between platforms that have different programming models. For example, services can hide the details about whether the component is a J2EE-based component or a .NET based component.
According to the definition that is provided by http://www.w3.org/TR/ws-gloss/#webservice, a web service is “a software system designed to support interoperable machine-to-machine interaction over a network”. The core of web services is the use of common transports (such as HTTP), data formats (XML, XML Schema), and protocols to create an interoperable way to integrate applications.
The information that is published about a web service provides details of what the service is and what it does. This can include information about the transport protocols that can be supported to send a message to the service, the wire format of this message expected by the service, whether and how the message has to be encrypted or signed.
A service is available at a particular endpoint in the network, and it receives and sends messages and exhibits behavior according to its specification.
The functional aspects of a service are specified using WSDL, and the constraints and conditions that are associated with the use of the service are specified through policies and configurations that you can attach to various parts of the WSDL. These are published so that the users of the service can discover and be given all the information they need to bind to that service.
HTTP and SMTP for basic network transport services
XML (Extensible Markup Language) as data format
Universal Description, Discovery and Integration (UDDI) for web service registries
The Web Service Description Language (WSDL) for service descriptions
The Simple Object Access Protocol (SOAP) for XML messaging and RPC
Web Services Policies
Software AG Web Services Stack is a toolkit that provides functionality for execution, configuration and management of web services. It handles the complex process of sending and receiving of web services requests in Software AG products. It allows everyone to do web services while knowing only a few of the details about the web services specifications.
The core part of the Web Services Stack runtime is the SOAP engine, based on Apache Axis 2. Incoming SOAP requests are processed by this SOAP engine. The SOAP request is given to the SOAP runtime and sent back to the client as a SOAP response message. If an error occurs a SOAP fault message is sent back to the client.
The option for generation, configuration and deployment of web services into Software AG Web Services Stack runtime allows the products to "wrap" an existing (legacy) server application and make it accessible to clients. Generally speaking, the products services are exposed as web services and deployed to a running Web Services Stack application.
