On 18.01.2012 03:35, DBinSD wrote:
> Does the felix implementation of the EventAdmin service support the delivery
> of events, asynchronously and in parallel to multiple listeners at once? It
This was addressed as part of RFC 157 ("Updates to EventAdmin") sometime
in 2010 and accepted, though I don't remember offhand what the
implementation status was/is. IIRC it was part of 4.3.
The solution added a set of constants that express basic delivery
behaviour/expectations. Not really enforceable end-to-end QoS constraints
(which are impossible in Java anyway) but better than nothing.
--snip--
5.2 Asynchronous Unordered Events
The following constants are added to EventConstants. This allows an Event
Handler to indicate that it is willing to relax the event ordering
requirements so that Event Admin can optimize delivery.
String EVENT_DELIVERY = "event.delivery"
Service Registration property specifying the delivery qualities requested
by an Event Handler service.
Event handlers MAY be registered with this property. Each value of this
property is a string specifying a delivery quality for the Event handler.
The value of this property must be of type String, String[], or
Collection<String>.
Since:
1.3
See Also:
DELIVERY_ASYNC_ORDERED
DELIVERY_ASYNC_UNORDERED
String DELIVERY_ASYNC_ORDERED = "async.ordered"
Event Handler delivery quality value specifying the Event Handler requires
asynchronously delivered events be delivered in order. Ordered delivery is
the default for asynchronously delivered events.
This delivery quality value is mutually exclusive with
DELIVERY_ASYNC_UNORDERED. However, if both this value and
DELIVERY_ASYNC_UNORDERED are specifed for an event handler, this value
takes precedence.
Since:
1.3
See Also:
EVENT_DELIVERY
String DELIVERY_ASYNC_UNORDERED = "async.unordered"
Event Handler delivery quality value specifying the Event Handler does not
require asynchronously delivered events be delivered in order. This may
allow an Event Admin implementation to optimize asynchronous event
delivery by relaxing ordering requirements.
This delivery quality value is mutually exclusive with
DELIVERY_ASYNC_ORDERED. However, if both this value and
DELIVERY_ASYNC_ORDERED are specifed for an event handler,
DELIVERY_ASYNC_ORDERED takes precedence.
Since:
1.3
See Also:
EVENT_DELIVERY
--snip--
Also see
http://stackoverflow.com/questions/7018762/when-to-use-osgi-eventadmin-and-when-not
for BJ's official answer.
hope this helps
Holger
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