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Subject: Re: Is an ObservationManager safe to use across threads?
From: Ian Boston <ieb@tfd.co.uk>
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Date: Fri, 15 Oct 2010 11:17:16 +0100
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To: users@jackrabbit.apache.org


On 15 Oct 2010, at 10:46, Vidar Ramdal wrote:

> Is this safe, or is the ObservationManager retrieved by
> session.getWorkspace().getObservationManager() tied to the session
> from which it was acquired?


In general its not safe since the session the observation manager was =
created with (which must stay logged in for the ObservationManager to =
remain active) is stored internally and used internally. There is one =
point where a check is made to ensure the same session is connected to =
dispatches,

however, in the case of removeEventListener although some new objects =
are created that are bound to the original session those objects are =
only used as keys to facilitate removal of the listener so you should be =
Ok.

BTW,
Using a session inside an event listener will almost certainly lead to =
massive blocking and potentially even deadlocks as the lower levels are =
protected (post 1.4 IIRC) to allow sessions to be shared between =
multiple threads without doing permanent damage, so think of the onEvent =
and the class/session that bound the on event as completely separate =
(and unfriendly) threads that will conflict. ie, be very careful what =
you share inside and outside the onEvent method.

HTH
Ian=