[jboss-dev-forums] [JBoss AS7 Development] - Re: Deployer chain cleanup

[David Lloyd]

David Lloyd [http://community.jboss.org/people/david.lloyd%40jboss.com] created the discussion

"Re: Deployer chain cleanup"

To view the discussion, visit: http://community.jboss.org/message/570623#570623

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In an ideal world we'd be able to use an interceptor-chain kind of pattern where each processor calls invokeNext() or whatever, and any error cleanup could be done in a finally block.  However the grim reality is that we could face stack exhaustion if we had a truly large number of extensions involved.  I think the next-best option is what you suggest: a cleanup() method which is called if a later processor fails.

So to restate:
1. Add a cleanup() method to DeploymentUnitProcessor
2. Each implementation of DUP should handle failure cleanly, so processDeployment is essentially atomic: either everything gets done or nothing (no partial state when an exception is thrown).
3. Then the implementation of cleanup() can perform a full cleanup safely, because it will only ever be called if processDeployment() had completed successfully *and* a later processDeployment() failed.
4. This implies that if a given processDeployment() fails, its cleanup() is *not* called, but the cleanup() methods on all the DUPs before the one that failed *are* called.

Make sense?
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