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Re: Deployer chain cleanup

created by David Lloyd in JBoss AS7 Development - View the full discussion

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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