Chapter 9 Introduction to Message Patterns
Overview
HydraExpress supports the four message patterns defined by the W3C WSDL Specification. These are:
• One-way. The service receives a message from the client, and the client expects no response. Characterized by a single input element.
• Request-response. The service receives a message from the client and sends a response. Characterized by one input element, followed by one output element.
• Solicit-response. The service initiates a message to the client and receives a response from the client. Characterized by an output element followed by an input element.
• Notification. The service initiates a message to the client, and expects no response. Characterized by a single output element.
This chapter introduces how to implement these four patterns in HydraExpress, using the shipped example WeatherSummary in the <installdir>\examples\webservices\WeatherSummary directory. The WeatherSummary example also demonstrates how HydraExpress handles complex types and how to auto-configure a listener.
The pattern request-response is most commonly used in Web services, and is illustrated further in most examples in this book, including the WeatherSummary example. See
Chapter 7 and
Chapter 8 , as well as the chapters in
Part IV, “Extending your Applications.” The patterns notification, one-way, and solicit-response are discussed in more detail in
Chapter 10 based on the WeatherSummary example.