[jboss-as7-dev] Important note for MSC Service authors

[Brian Stansberry]

Is use of LifecycleContext.execute(Runnable) recommended? For anyone 
doing as you say and using LifecycleContext.asynchronous() and 
complete(), using that execute() method is going to be a path of least 
resistance.

On 4/13/11 2:55 PM, David M. Lloyd wrote:
> When writing MSC service implementations, your start() and stop()
> methods must never block.  This means these methods must not:
>
> - Establish or use network connections
> - Wait for network connections
> - Sleep
> - Wait on a condition
> - Wait on a count down latch
> - Call any method which may do any of the above
> - Wait for termination of a thread pool or other service
> - Wait for another service to change state!
>
> If your service start/stop involves any of these tasks, you must use the
> asynchronous start/stop mechanism (context.asynchronous()) and do one of
> the following:
>
> - Initiate your task in start()/stop(), and utilize a callback (NIO,
> ThreadPoolExecutor.terminated(), etc.) to call context.complete() when
> your start/stop completes instead of blocking
> - Delegate your blocking task to a thread pool (Executor) which calls
> context.complete() when done
> - Use proper dependencies instead of explicitly waiting for services in
> your start/stop
>
> Failure to do so can cause startup delays and can even lock up the MSC
> state machine!  If you are unsure what the best approach is for your
> problem, ping me in #jboss-as7 or #jboss-msc and I'll help you out.
>


-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat