B2B Integration : A Practical Guide to Collaborative E-commerce

334 B2B Integration — A Practical Guide to Collaborative E-commerce
the format of publishing the operations of a service with their respective
parameters and data types, defining the location and binding details of
the service.
WSDL syntax enables both the messages and the operations on the
messages to be defined abstractly, so that they can be mapped to
multiple physical implementations, such as SOAP, HTTP and MIME.
WSDL is independent of the underlying protocol and encoding
requirements, thereby enabling dynamic cross-platform integration.
11.5.1. WSDL schema
A WSDL XML schema (as defined by IBM and Microsoft) includes the
following parts:
• Types — a container for the different data types contained in the
message, which can be in the form of XML schemas or some type
system (such as XSD);
• Message — an abstract description of the data being exchanged that
can be presented as full documents or as arguments mapped to an
operation invocation;
• Operation — an abstract definition of an action (such as a business
process) supported by a Web service;
• Port Type — an abstract collection of operations that are mapped to
one or more endpoints, which enables the operations to map to one
or more transport protocols;
• Binding — used to attach a concrete protocol and data format
specification for a port type;
• Port — an endpoint defined as a combination of binding a
network address, which provides the target address of the service
communication; and
• Service — a collection of related endpoints that map the binding to
the port and include any extensibility definition.
11.5.2. WSDL and UDDI
WSDL complements the UDDI standard by providing a uniform way of
describing the interface and protocol bindings of network services.