Web services development approaches
There are two general approaches to Web service development: top-down and bottom-up:
| In the top-down approach, a Web service is based on the Web service interface and XML types, defined in Web Services Description Language (WSDL) and XML Schema Definition (XSD) files. The developer first designs the implementation of the Web service by creating a WSDL file using the WSDL editor. The developer can then use the Web Service wizard to create the Web service and skeleton Java classes to which the developer can add the required code.The developer then modifies the skeleton implementation to interface with the business logic. |
The top-down approach allows for more control over the Web service interface and the XML types used, and is the recommended approach for developing new Web services.
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| In the bottom-up approach, a Web service is created based on the existing business logic in Java beans or EJBs. A WSDL file is generated to describe the resulting Web service interface. |
The bottom-up pattern is often used for exposing existing function as a Web service. It might be faster, and no XSD or WSDL design skills are needed. However, if complex objects (for example, Java collection types) are used, then the resulting WSDL might be hard to understand and less interoperable.
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