Hello Joao,
Are you using demarcation and saving the transaction state with separate containers?
Regards,
Rich Katz
-------Original Message-------
From: Joao Clemente <[EMAIL PROTECTED]>
Sent: 08/01/03 01:11 PM
To: [EMAIL PROTECTED]
Subject: [JBoss-user] Pattern advice for ejb recovery wanted
>
> Well, I think I would like some feedback on how are the real
implementations
of failover recovery code out there.
We though of three approaches:
1 - use ejbActivate: The method would see if the ojbect is in a
non-consistent state and would revover if necessary.
2 - intercept every method with a initial test: Each method would start
with "if recoveryNeeded() then recover"
3 - wrap a transient variable with a getter method that would recover
that
variable.
getAVariable() {
if (aVariable==null) recover();
return aVariable
}
We still think that (1) is the best choice, but we had problem using it.
Our
ejb's have references for each other and they get each other variables
when
recovering so we would get locked while using ejbActivate.
I think I can describe the problem like this: With 2 ejb's, where both
need
transient values that are found in the other, and where a client can start
calling either one, we have:
EJB1 {
getValue2();
businessMethod1(); // calls businessMethod2()
}
EJB2 {
transient value2;
recover(); // needs to get the value that is provided by EJB1:
EJB1.getValue2();
businessMethod2(); // manipulates value2
}
In a failover situation, if I have a call to EJB1.businessMethod1(), what
is the pattern that allows to recover value2 ?
--
Joao Clemente - jpcl at rnl ist utl pt
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