well u can always call the remote service/method a number of times in case
u get a remote exception -- but the fact u have to consider is -- whether
the method/service u are calling is idempotent or not. It may happen that ur
request has actually been seviced and commited -- and the server/service
crashed before returning. In that case though ur request has been serviced
the client gets a remote exception. So if the client calls again then the
action will be performed twice. So if u are going for that particular design
-- do make ur service idempotent.
BTW is there any genric rule/way to make service idempotent?
TIA
Anamitra
-----Original Message-----
From: David Van Couvering
To: [EMAIL PROTECTED]
Sent: 8/18/00 7:03 PM
Subject: Re: Using Dynamic Proxies for Fault Tolerance
>From what I understand you *can* throw RemoteException in an
implementation
method, you just don't *have* to.
The other thing you can do is re-throw the RemoteException as an
EJBException...
Dynamic proxies are great, I would definitely give them a shot.
David
> -----Original Message-----
> From: A mailing list for Enterprise JavaBeans development
> [mailto:[EMAIL PROTECTED]]On Behalf Of James Cook
> Sent: Thursday, August 17, 2000 7:41 AM
> To: [EMAIL PROTECTED]
> Subject: Using Dynamic Proxies for Fault Tolerance
>
>
> I could use some advice on a pattern to use to enable fault
> tolerance on the
> client-side of the EJB scenario. My clients access session beans
through a
> Facade (FundBroker) interface that is implemented on my client by
> a class named
> FundBrokerImpl.
>
> If the client invokes a method in FundBrokerImpl, the method
> simply makes the
> call against the appropriate session bean. If I receive a remote
> exception, I
> attempt to resubmit the request a number of times before trying
> more drastic
> actions. I understand that I could put the following code in all
> of my methods:
>
> while (attempts < 3) {
> try {
> remote.getSomeValue();
> return;
> } catch (RemoteException rx) {
> attempts++;
> }
> }
> // handle fatal error
>
> I want to use Dynamic Proxies in JDK 1.3 to leverage the proxy
> pattern so I can
> eliminate some of the monotonous coding. I also want to eliminate
> the client
> (but not this proxy) from dealing with any extreme fatal errors.
> Therefore, one
> stipulation that I have is that the method signature in
> FundBroker cannot throw
> a RemoteException.
>
> FundBroker: Value getSomeValue();
>
> The problem is that the method signature in the implementation
> class also cannot
> throw RemoteException. Unfortunately, this method will contain
> the call to the
> remote ejb interface, which most certainly *will* throw
> RemoteException. Of
> course, the compiler won't let this conflict pass unnoticed.
>
> I know of several ways to get around this pattern without
> resorting to Dynamic
> Proxies, but I was wondering if anyone can think of a way I can
> use this very
> cool feature.
>
> thanks,
> jim
>
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