tailieunhanh - Flash Builder 4 and Flex 4 Bible- P19

Flash Builder 4 and Flex 4 Bible- P19: When Macromedia first released Flash MX in 2002, the product was branded as the new way to build Rich Internet Applications (known by the acronym RIA). The term was invented at Macromedia to describe a new class of applications that would offer the benefits of being connected to the Internet, including access to various types of Web-based services, but would solve many of the nagging issues that had been inherent in browser-based applications since the mid-1990s | Chapter 27 Using the Message Service with BlazeDS FIGURE An application sending and receiving filtered messages using subtopics Tracing Messaging Traffic As with all network communications between Flex clients and application servers you can use the TraceTarget component to enable tracing of messaging traffic. Follow these steps to trace messaging 1. Open any Flex application that uses the Message Service. 2. Add an s TraceTarget tag as a child of the application s fx Declarations element. 3. Set any optional values that determine what metadata is included with each tracing message. For example this declaration of the TraceTarget object would cause tracing messages to display date and time information fx Declarations s TraceTarget includeDate true includeTime true fx Declarations 4. Run the application in debug mode. 5. Watch Flash Builder s Console view to see the tracing output. Figure shows the resulting output in Flash Builder s Console view. 871 Part IV Integrating Flex Applications with Application Servers FIGURE Tracing output from a messaging application Summary In this chapter I described how to create and deploy Flex client applications that use the Message Service with BlazeDS. You learned the following The Message Service is implemented in both LiveCycle Data Services and BlazeDS. The Message Service enables you to share data between multiple connected Flex applications in real time or almost real time. Flex applications that use the Message Service can be integrated with other applications that are built in Java and ColdFusion. A Flex application sends messages using the Flex framework s Producer component. A Flex application receives and processes messages using the Flex framework s Consumer component. You can send and receive both simple and complex data. Messages can be filtered at the server with the Consumer component s selector property or with subtopics. You can use the TraceTarget logger target to turn on tracing of message .