Day 21. Message-Style Web Services and Web Service Registries

Yesterday, you learned about Web Service architecture and you created your own RPC-style Web Services. Although RPC-style interaction is a common style of distributed interaction, many applications also use message-oriented mechanisms to decouple parts of the system. Today, you will use the same Web Service protocols to perform a message-style interaction.

The final part of your exploration of Java Web Services will examine the use of XML-based registries. Part of the Web Service architecture involves the lookup of Web Service information in a registry, but the Web Service information you used was not obtained that way. Today, you will see how such registration and retrieval can be simplified using a standard Java API.

Today, you will

• Look at how message-style Web Service interactions differ from RPC-style interactions

• Send and receive SOAP messages using the SOAP with Attachments API for Java (SAAJ)

• Examine the role of Web Service registries

• Walk through code based on the Java API for XML Registries (JAXR) that registers and retrieves information using a UDDI registry

Today's intention is to use message-based Web Services (as opposed to RPC-based ones) and to interact with a Web Service registry.