It is more important for us to know what
functionality is installed and available before parts of the application
execute then it is for us to support dynamism. I would like to keep the
dynamism if we can, but to do that and provide reliable execution I think the
application would need to guarantee that all services known through the bundle
manifests will be initialized before we start processing. I guess using extensions
might be a better fit.
I’m not sure if we need DS to
synchronously register services as much as some way to listen to DS events or
know its state, like is it just sitting around waiting for more bundles to be
activated or deactivated. I was focused on services being managed by DS
since I thought DS would know weather it was done initializing all services listed
in the active bundles’ manifest files and then we would be able to say to
users which may supply functionality, well if you use DS then we could
guarantee that we wouldn’t start until DS had initialized your services.
Thanks,
Otto
From:
equinox-dev-bounces@xxxxxxxxxxx [mailto:equinox-dev-bounces@xxxxxxxxxxx] On Behalf Of BJ Hargrave
Sent: Wednesday, September 03,
2008 7:22 AM
To: Equinox development mailing
list
Subject: Re: [equinox-dev] When is
DS done loading services?
The whole point of services is that the are dynamic.
The fact the DS is "processing" them on behalf of some bundle does
not mean that another bundle should know or observe that.
Bundles
which depend upon a service need to deal with that service's dynamism. You
can't assume a bundle's activator or starting a bundle will synchronously
register some services. I would not support an option for DS to synchronously
register services during bundle start as this means people will improperly use
that.
You
may also be seeing an impedance mismatch between the lifecycle of extensions
and services. Extensions become active when the bundle is resolved while
services become active only when the bundle is started. Switching to use
extensions will not allow for dynamism (unless you want to write all the code
to use the extension registry API to do so.)
You
may be able to use startlevels to mitigate the issue (make sure all bundles
providing service B are started before bundles using B), but this is also a
hack. It would be better if service A dealt with the dynamics of service B such
that service A has a dynamic dependency on service B and is able to accept B's
being registered and unregistered at any time.
--
|
From:
|
Stoyan Boshev <s.boshev@xxxxxxxxxxx>
|
|
To:
|
Equinox development mailing list <equinox-dev@xxxxxxxxxxx>
|
|
Date:
|
2008/09/03 07:51 AM
|
|
Subject:
|
Re: [equinox-dev] When is DS done loading services?
|
Hi
Otto,
I guess your problem is connected to the
asynchronous processing of the
DS services.
As far as I understand the situation is: your
application bundles are
started, then your application is started but at
this moment not all of
the DS services are inited yet because they are
being asynchronously
processed.
Unfortunately currently there is no way to find
out when DS completes
the DS services processing.
I think if there was an option that DS bundle
process the DS services in
the started bundles synchronously, it would solve
your problem. So I
will open bug(enhancement) about that and
hopefully this will be
implemented soon.
As a possible workaround you could observe the
running threads and when
the thread with name "Component Resolve
Thread" disappears this would
mean that DS bundle has no more work to do and
eventually all of your DS
services are processed. I realize this is not a
clean solution (that's
why I call it workaround) but at this moment I
cannot find out a more
appropriate working solution without modifications
in the DS bundle.
Stoyan
Cortez, Otto wrote:
> I made a post to the Eclipse newcomers group
a few weeks ago, but did
> not get a response. I don’t know
if this is the appropriate place for
> this question, but hopefully someone can
point me in the right direction.
>
>
>
> We are building a headless RCP application
and we would like to use DS
> to make functionality available. The
problem we are running into is
> that not all of the services we declared
through DS get loaded and are
> visible before our application executes.
>
>
>
> For example, I have a service A which needs
0..n instances of another
> service B. The issue I'm running into is that
if the implementations of
> service B are spread across several bundles,
then the service A will not
> have seen all instances of service B when it
is called since the
> application starts (and sometimes ends)
running before DS is done
> looking through all the bundles and
registering all the services in the
> active bundles.
>
> Is there a way to know when declarative
services is done looking through
> the active bundles and loading the services
found in them? Am I missing
> something?
>
>
>
> It seems that using the plug-in registry may
solve this issue. Is that
> perhaps a better way to go?
>
>
>
> Thanks,
> Otto
>
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--
---------------------------------------------------------
dipl. eng. Stoyan Boshev . Department manager
ProSyst Labs EOOD
1606 Sofia,
Bulgaria . 48
Vladajska Str.
Tel. +359 2 953 05 88; Fax +359 2 953 26 17
Mobile: +359 88 898 29 17
http://www.prosyst.com .
s.boshev@xxxxxxxxxxx
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