Sunday, January 6, 2008

Programming Weblogic Web services

You develop a WebLogic Web Service, by using standard J2EE components, such as stateless session EJBs, and Java classes. Because WebLogic Web Services are based on the J2EE platform, they automatically inherit all the standard J2EE benefits, such as a simple and familiar component-based development model, scalability, support for transactions, life-cycle management, easy access to existing enterprise systems through the use of J2EE APIs (such as JDBC and JTA), and a simple and unified security model.
A single WebLogic Web Service consists of one or more operations; you can implement each operation using different back-end components and SOAP message handlers. For example, an operation might be implemented with a single method of a stateless session EJB or with a combination of SOAP message handlers and a method of a stateless session EJB.

Here is what happens when a client application invokes this type of WebLogic Web Service operation:

1. The client application sends a SOAP message request to WebLogic Server over HTTP. Based on the URI in the request, WebLogic Server identifies the Web Service being invoked.
2. The Web Service reads the SOAP message request and identifies the operation that it needs to run. The operation corresponds to a method of a stateless session EJB or a Java class, to be invoked in a later step.
3. The Web Service converts the operation's parameters in the SOAP message from their XML representation to their Java representation using the appropriate deserializer class. The deserializer class is either one provided by WebLogic Server for built-in data types or a user-created one for non-built-in data types.
4. The Web Service invokes the appropriate back-end component method, passing it the Java parameters.
5. The Web Service converts the method's return value from Java to XML using the appropriate serializer class, and packages it into a SOAP message response.
6. The Web Service sends the SOAP message response back to the client application that invoked the Web Service.

For further information, browse through this beautiful doc provided by BEA.

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