Web Services Description Language (WSDL)

Web Services Description Language (WSDL) is a standard specification for describing networked, XML-based services. It provides a simple way for service providers to describe the basic format of requests to their systems regardless of the underlying run-time implementation.

WSDL defines an XML format for describing network services as a set of endpoints that operate on messages that contain either document-oriented or procedure-oriented information. The operations and messages are first described abstractly and then bound to a concrete network protocol and message format in order to define an endpoint. Related concrete endpoints are combined into abstract endpoints (services). WSDL is extensible to allow description of endpoints and their messages, regardless of which message formats or network protocols are used to communicate. This means that interfaces are defined abstractly using XML schema and then bound to concrete representations that are appropriate for the protocol.

WSDL allows a service provider to specify the following characteristics of a Web service:

• The name of the Web service and addressing information
• The protocol and encoding style to be used when accessing the public operations of the Web service
• The type information such as operations, parameters, and data types comprising the interface of the Web service

WSDL documents allow developers to expose their applications as network-accessible services on the Internet. Through UDDI and WSIL, other applications can discover WSDL documents and bind with them to execute transactions or perform other business processes.

This development platform supports and encourages the development and use of WS-I compliant WSDL. Business service providers can deploy Java™ beans and enterprise beans as a Web service and generate a WSDL document that describes the service. They can also generate Java and enterprise bean skeletons from an existing WSDL file. A business service client can generate a Java proxy from a WSDL document, thereby providing an easy-to-use Java interface to the Web service. The Java interface hides the network communications details from the client enabling the business service provider to focus on business and process portions of the application.

In addition to providing tools to create Web services, the workbench provides a WSDL editor that allows you to create WSDL files using a graphical interface, a WSDL validator that ensures that your WSDL file is semantically correct and optionally checks for WS-I compliance, and the Web Services Explorer which allows you to dynamically test Web services without requiring you to generate a proxy.

The workbench supports WSDL 1.1. For more information on the WSDL specification, refer to www.w3.org/TR/wsdl

• Web Services Description Language (WSDL) reference
  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. This allows the reuse of abstract definitions: messages, which are abstract descriptions of the data being exchanged, and port types which are abstract collections of operations.