WSDL documents are correctly formed XML documents, which again aids in
developing enterprise applications in a Service Oriented Architecture. Correctly
formed XML documents can be read and parsed automatically by computers, which
allows clients to look up and consume web services automatically (for example, by
using a uddi registry) or allows the Normalized Message Router (see Chapter 3) to
pass standardized messages between the different JBI components (for example,
Service Engines and Binding Components).
WSDL was first proposed in March 2001 as a note to the W3C (http://www.w3.org/
wsdl) by Ariba, IBM, and Microsoft. In their W3C note, they describe WSDL as:
??¦an XML format for describing network services as a set of endpoints operating
on messages containing either document-oriented or procedure-oriented
information. The operations and messages are described abstractly, and then bound
to a concrete network protocol and message format 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 what
message formats or network protocols are used to communicate.
Why WSDL?
The key benefits of using WSDL are:
WSDL is XML-based: being XML-based means any system that can read and
interpret XML, can read and interpret WSDL documents.
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