Is it ok to bubble up the exception to the top of the stack?

Question

Is it ok to let exception bubble up to the top of the stack instead of catching it in every method?.. Should we do it in any case? ..Are there any subtle issues or side effects with this approach (e.g. loss of details of the exception, stack trace or inner exception details etc.) ?

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Though my question is general, the scenario in my case at present is as follows:

I am moving existing WSE3 web service to the WCF and so y clients are WSE3 clients.

I have added a behavior so that the FaultException will be communicated to the client side whenever it occurs in the WCF service. When there is an exception in the OperationContract method, I get exception message at client side without any problem. But whenever it occurs in the methods other than the OperationContracts, I get security related problem somehow. I am not able to identify the exact cause.

However, as a work around I thought to throw exceptions from OperationContract only and let exceptions bubble up to the OperationContract.

Answer 1

Is it ok to let exception bubble up instead of catching it in every method?

Please Don't catch excpetions in every method! - you should only ever catch exceptions if you can do something useful with it, for example:

• Handle it (i.e. not rethrow it)
• Add some important contextual information

I've maintained applications where every nethod was surround with a try-catch block, and I literally mean every method:

public void DoSomething()
{
    try
    {
        throw new NotImplementedException();
    }
    catch (Exception ex)
    {
        throw ExceptionHandler.CreateException(ex, "DoSomething");
    }
}

Catching exceptions like this is utterly pointless and does nothing except make your code harder to read and your exceptions harder to trace.

In the case where you exception has to pass some interprocess boundary (such as in a WCF service) then at the point where your exception is exposed to the world you might want to first catch, log and then rethrow the exception in a compatible format for the IPC boundary so that you have a log of all failures in your servivce

In many cases however there is an alternative mechanism designed for just this purpose- WCF has the IErrorHandler interface which can be registered to catch and log all unhandled exceptions in a consistent way without needing a try-catch block in each exposed method.

Answer 2

If you have a full applications (GUI, business, data) let it bubble up to the UI and handle it here on the events. This gives you an opportunity to display a message to the user at the same time. It also catches it to the point of action origin (i.e. when user did action X this occured). Catching it in every method is too CPU intensive and unnecessary since you can just log the stacktrace to find the origin anyway. If you are making middleware application then try to handle it at the interface or bubble it out - depending on how the middleware will be used.