Observers And Exceptions

[refactoring of ObserversThrowLocalExceptions]

In the recent discussions about exceptions, problems with the ObserverPattern have come to light.

An Observable is responsible for notifying its observers whenever relevant state changes occur. Since exceptions are, in essence, violations of the standard control flow, they present problems in for such radically uncoupled objects.

There are two major consequences:

• methods on the Observable object should not throw exceptions unless they TidyUpBeforeThrowing
• Either ObserversShouldNeverThrowExceptions or ObservablesShouldUseATwoPhaseCommit

WilliamGrosso

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How about ExceptionReporter technique?

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CategoryException CategoryPattern