Hi,
I have recently played around with optional reference elements (to get around
Blueprint automatically deregistering dependent services). One oddity I have
encountered is the behaviour when unsatisfied. My initial assumption as well as
that of people I have talked to was that a ServiceUnavailableException would be
thrown straight away. However, section 121.10.1 of the Blueprint spec mandates
that references with optional availability should wait in the same way that
mandatory references do:
"When an operation is invoked on an unsatisfied proxy from a reference
manager (either optional or mandatory), the invocation must block until either
the reference becomes satisfied or a time-out expires (whichever comes first).
[...]"
However, this behaviour does not work with our Blueprint implementation and as
far as the code below in ReferenceRecipe#getService is concerned can never work:
if (isStarted() && trackedServiceReference == null &&
metadata.getTimeout() > 0
&& metadata.getAvailability() ==
ServiceReferenceMetadata.AVAILABILITY_MANDATORY) {
blueprintContainer.getEventDispatcher().blueprintEvent(new
BlueprintEvent(BlueprintEvent.WAITING,
blueprintContainer.getBundleContext().getBundle(),
blueprintContainer.getExtenderBundle(), new String[] { getOsgiFilter() }));
monitor.wait(metadata.getTimeout());
}
Which to me suggests we are not implementing the spec but I am sure I have
missed something :-) Any thoughts?
Regards,
Valentin
