What is the interface

The interface is an abstract model of the service:

• references the set of messages that a service sends or receives, and group them into operations.
• defines the exchange pattern for the abstract messages: sequence, direction, and cardinality

<interface name="Service1HttpGet">
  <operation name="getResult"
	  pattern="http://www.w3.org/2003/04/wsdl/in-out">
      <input message="s0:getResultHttpGetIn">
         <part name="uri" type="xsd:anyURI"/>
      </input>
      <output message="s0:getResultHttpGetOut">
         <part element="s0:getResultResponse"/>
      </output>
  </operation>
</interface>

WSDL 1.2 improves interfaces with inheritance: no overloading (if two operations have the same qname, then their components must be equivalent, i.e. the abstract model are equals).

Issue: Should we introduce properties?