21.3.3 The Flow Stack Visual Model

   To visualize the general flow rules, think of each Interceptor as being put on a Flow Stack when a starting interception point completes successfully. (An ORB need not implement the Flow Stack. It is presented simply as a visual cue.) An ending interception point is called for each Interceptor in the stack. If a starting interception point is called for all Interceptors, then all Interceptors will have an ending interception point called. If one of the Interceptors raises an exception during the invocation of its starting interception point, only those Interceptors on the stack at that point will be popped and have an ending interception point called.