This chapter explains how to retrieve information that is used to access and consume a WSIT-enabled web service and provides pointers to examples that demonstrate how to bootstrap and configure WSIT-enabled clients from Web Services Description Language (WSDL) files.
The following topics are covered in this chapter:
Web services expose one or more endpoints to which messages can be sent. A web service endpoint is an entity, processor, or resource that can be referenced and to which web services messages can be addressed. Endpoint references convey the information needed to address a web service endpoint. Clients need to know this information before they can access a service.
Typically, web services package endpoint descriptions and use a WSDL file to share these descriptions with clients. Clients use the web service endpoint description to generate code that can send SOAP messages to and receive SOAP messages from the web service endpoint.
To create a web service client that can access and consume a web service provider, you must obtain the information that defines the interoperability requirements of the web service provider. Providers make this information available by means of WSDL files. WSDL files may be made available in service registries or published on the Internet using a URL (or both). You can use a web browser or NetBeans IDE to obtain WSDL files.
A WSDL file contains descriptions of the following:
Network services: The description includes the name of the service, the location of the service, and ways to communicate with the service, that is, what transport to use.
Web services policies: Policies express the capabilities, requirements, and general characteristics of a web service. Web service providers use policies to specify policy information in a standardized way. Policies convey conditions on interactions between two web service endpoints. Typically, the provider of a web service exposes a policy to convey conditions under which it provides the service. A requester (a client) might use the policy to decide whether or not to use the service.
Web Services Metadata Exchange (WS-MEX) is the protocol for requesting and transferring the WSDL from the provider to the client. This protocol is a bootstrap mechanism for communication. When the type of metadata desired is clearly known (for example, WS-Policy), a client request may indicate that only that type should be returned.
The following sections, found in other chapters of this tutorial, explain how to create a client from a WSDL file using the example files in the tutorial bundle:
Creating a Client to Consume a WSIT-Enabled Web Service shows how to create a client from WSDL using a web container and the NetBeans IDE.
Creating a Client from WSDL shows how to create a client from WSDL using only a web container.