The Context Package
Context is the circumstances in which something happens. When we are talking about a program, the context is the program environment, settings, and so on. For a server program (an HTTP server responding to a client request, an RPC server responding to function calls, etc.) or a program that responds to user requests (an interactive program, a command-line application, etc.), you can talk about a request-specific context. A request-specific context is created when the server or program starts processing a particular request and terminates when the processing ends. The request context contains information such as a request identifier that helps you identify log messages generated while processing a request, or the identity of the caller so you can determine the access rights of the caller. One of the uses of the context package is to provide an abstraction of such a request context, that is, an object that keeps request-specific data.
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