Web Services Description Language (WSDL) is an XML-based specification schema for describing a web service. WSDL defines a web service as a set of endpoints or ports operating on messages. A port is defined by associating a network address (such as http://api.google.com/search) with a reusable binding, and a collection of ports define a service. WSDL is extensible to allow the description of endpoints and their associated messages regardless of what message formats or network protocols are used to communicate.
The structure of a WSDL file consists of abstract descriptions followed by bindings to a concrete message format and network protocol. The IDE can create a WSDL file for you.