Summary

This chapter compared the features of the Enterprise Library Exception Handling Application Block to its predecessor, the Exception Management Application Block, covered the design of the application block, and described how to configure and develop an application to use it. The design for this application block is based in large part on the guidance found in the Exception Management in .NET Architecture Guide. The major principle that you should understand from this chapter is that the Exception Handling Application Block allows an application to decouple when it handles an exception from how it handles an exception.

The chapter reviewed the features that existed in the Exception Management Application Block that are not mentioned in the Exception Handling Application Block, and it highlighted where new functionality replaced some of the functionality that previously existed and which functionality was moved to the Logging and Instrumentation Application Block. It included a detailed analysis of the design for the ExceptionPolicy, ExceptionHandler, and ExceptionFormatter classes and showed how the interfaces for the ExceptionFormatter and ExceptionHandler provide extension points that you can use to its advantage. It also covered how to configure the Exception Handling Application Block and how developing an application to use it only requires understanding an extremely simple interface with a single method. Emphasis was placed on the fact that very little code actually needs to be written to use the Exception Handling Application Block. As exception policies change over time, the code that initiates these exception policies does not; only the configuration for how these exception policies run needs to be modified.