[jboss-user] [JBossCache] - Re: POJO Mutations

llowrey0 do-not-reply at jboss.com
Tue Jul 25 13:15:39 EDT 2006


Consider two scenarios.

First:

(i) Class A has member 'int state' where 'state' is set using a set of 'final static int' constants.

(ii) Now, A gets altered so that 'state' is now an instance of an enum 'STATE {...}'.

A node with class version (i) adds an instance of A into the PojoCache. What happens when a node with version (ii) tries to retrieve that same instance of A? Or, similarly, what happens when the CacheLoader tries to read a version (i) object when it has only the version (ii) class in its ClassLoader?

Second:

(i) Class B extends A

Say we need to change the structure so that we introduce a new class, C, so that...

(ii) Class B extends C extends A

If I have a serialized instance of (i) and try to deserialize with an instance of (ii) I'm going to have some heartburn. Granted, PojoCache is not (de)serializing, but I don't understand the logic well enough to understand how it will treat this case.

Basically, as classes evolve over time, how does PojoCache handle the adding, deleting, and retyping of member fields?

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