subject:"Re\: \[osgi\-dev\] How to determine when a new service instance has been activated\?"

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Tim Jones

thanks Ray, will think it over. 

Tim 

From: "Raymond Auge" <raymond.a...@liferay.com> 
To: "OSGi Developer Mail List" <osgi-dev@mail.osgi.org> 
Sent: Wednesday, 25 January, 2017 12:43:33 PM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

BTW, a very nice way of handling this queuing (i.e. async) might be OSGi 
promises! 

- Ray 

On Tue, Jan 24, 2017 at 3:39 PM, Raymond Auge < [ 
mailto:raymond.a...@liferay.com | raymond.a...@liferay.com ] > wrote: 

On Tue, Jan 24, 2017 at 3:23 PM, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz 
| tim.jo...@mccarthy.co.nz ] > wrote: 

BQ_BEGIN

Okay let's say for example that incoming data needs to stored in separate 
database schemas/partitions depending upon some value within the data. We don't 
know in advance what these values are so we can't pre create the 
schemas/partitions before server startup, so instead when a new value arrives 
we create the database schema/partition and tables, functions, assign roles 
etc, then create an associated JPA persistence unit + dependent services. 

I'd be very hesitant to have all this work be the result of a single method 
call. Sounds scary! 

I'd probably do something like: 
- identify that a schema is needed by looking at the data 
- queue schema creation up in a schema queue 
- queue up the data in data queue 
- schema queue consumer does all that setup work, or if it had already been 
done, skip it 
- once ready create a data queue consumer 
- data queue consumer notices its data in the queue and process it 

Just an idea! 
- Ray 

BQ_BEGIN

Tim 

From: "Raymond Auge" < [ mailto:raymond.a...@liferay.com | 
raymond.a...@liferay.com ] > 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Wednesday, 25 January, 2017 12:09:17 PM 

Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

On Tue, Jan 24, 2017 at 3:08 PM, Raymond Auge < [ 
mailto:raymond.a...@liferay.com | raymond.a...@liferay.com ] > wrote: 

BQ_BEGIN

On Tue, Jan 24, 2017 at 3:00 PM, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz 
| tim.jo...@mccarthy.co.nz ] > wrote: 

BQ_BEGIN

Ray can you please explain a little more what you mean by 'manifest the 
schemas'? One thing I should have said is we don't know in advance of server 
startup as to what schemas will be needed. 

BTW I have read [ 
http://www.coding-dude.com/wp/java/liferay/liferay-multi-tenancy-setup-with-shards/
 | 
http://www.coding-dude.com/wp/java/liferay/liferay-multi-tenancy-setup-with-shards/
 ] 

BQ_END

That article is a little dated but it's fine :) 

What I mean to suggest is that rather than having creation of schema be a side 
effect caused by some method call, it could probably be better modelled by some 
agent specializing in schema who once it's built a schema exposes it as an OSGi 
service. 

This way other components interested in schema can have real service 
dependencies on those concert services. 

BQ_END

auto-correct gaf: ...schema services... 

BQ_BEGIN

I hope that is a little more clear. 

However, I've been slightly confused by the implication of your statement: 
> we don't know in advance of server startup as to what schemas will be needed 

My question to that is; isn't that a function of somebody providing one or not 
Otherwise, I can't see how you'd magically get a schema as a result of a 
function call? To me that feels a little reverse. I think the schema should 
arrive and then others who may need it would be satisfied or not. 

- Ray 

BQ_BEGIN

Tim 

From: "Raymond Auge" < [ mailto:raymond.a...@liferay.com | 
raymond.a...@liferay.com ] > 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Wednesday, 25 January, 2017 11:20:37 AM 

Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

On Tue, Jan 24, 2017 at 2:17 PM, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz 
| tim.jo...@mccarthy.co.nz ] > wrote: 

BQ_BEGIN

Actually the remote service still calls the same 'top level' component but it 
is this component that will make the choice as to which set of instance of 
services are ultimately exercised. At the risk of going too far off topic but 
to illustrate the requirement, the application is a multi-tenant system that 
needs to be able to create and access new db schemas on the fly. I don't wont 
the call to create the new db schemas and the associated services to return 
until they have been created. 

BQ_END

A nice way to do this is to flip the problem on it's head and manifest the 
schemas, once ready, as a services and have interested components declare 
references to those services. 

- Ray 

BQ_BEGIN

Tim 

From: "Christian Schneider" < [ mailto:ch...@die-schneider.net | 
ch

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Tim Jones

Okay let's say for example that incoming data needs to stored in separate 
database schemas/partitions depending upon some value within the data. We don't 
know in advance what these values are so we can't pre create the 
schemas/partitions before server startup, so instead when a new value arrives 
we create the database schema/partition and tables, functions, assign roles 
etc, then create an associated JPA persistence unit + dependent services. 

Tim 

From: "Raymond Auge" <raymond.a...@liferay.com> 
To: "OSGi Developer Mail List" <osgi-dev@mail.osgi.org> 
Sent: Wednesday, 25 January, 2017 12:09:17 PM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

On Tue, Jan 24, 2017 at 3:08 PM, Raymond Auge < [ 
mailto:raymond.a...@liferay.com | raymond.a...@liferay.com ] > wrote: 

On Tue, Jan 24, 2017 at 3:00 PM, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz 
| tim.jo...@mccarthy.co.nz ] > wrote: 

BQ_BEGIN

Ray can you please explain a little more what you mean by 'manifest the 
schemas'? One thing I should have said is we don't know in advance of server 
startup as to what schemas will be needed. 

BTW I have read [ 
http://www.coding-dude.com/wp/java/liferay/liferay-multi-tenancy-setup-with-shards/
 | 
http://www.coding-dude.com/wp/java/liferay/liferay-multi-tenancy-setup-with-shards/
 ] 

That article is a little dated but it's fine :) 

What I mean to suggest is that rather than having creation of schema be a side 
effect caused by some method call, it could probably be better modelled by some 
agent specializing in schema who once it's built a schema exposes it as an OSGi 
service. 

This way other components interested in schema can have real service 
dependencies on those concert services. 

BQ_END

auto-correct gaf: ...schema services... 

BQ_BEGIN

I hope that is a little more clear. 

However, I've been slightly confused by the implication of your statement: 
> we don't know in advance of server startup as to what schemas will be needed 

My question to that is; isn't that a function of somebody providing one or not 
Otherwise, I can't see how you'd magically get a schema as a result of a 
function call? To me that feels a little reverse. I think the schema should 
arrive and then others who may need it would be satisfied or not. 

- Ray 

BQ_BEGIN

Tim 

From: "Raymond Auge" < [ mailto:raymond.a...@liferay.com | 
raymond.a...@liferay.com ] > 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Wednesday, 25 January, 2017 11:20:37 AM 

Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

On Tue, Jan 24, 2017 at 2:17 PM, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz 
| tim.jo...@mccarthy.co.nz ] > wrote: 

BQ_BEGIN

Actually the remote service still calls the same 'top level' component but it 
is this component that will make the choice as to which set of instance of 
services are ultimately exercised. At the risk of going too far off topic but 
to illustrate the requirement, the application is a multi-tenant system that 
needs to be able to create and access new db schemas on the fly. I don't wont 
the call to create the new db schemas and the associated services to return 
until they have been created. 

BQ_END

A nice way to do this is to flip the problem on it's head and manifest the 
schemas, once ready, as a services and have interested components declare 
references to those services. 

- Ray 

BQ_BEGIN

Tim 

From: "Christian Schneider" < [ mailto:ch...@die-schneider.net | 
ch...@die-schneider.net ] > 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Wednesday, 25 January, 2017 11:01:20 AM 

Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

If the call is via jms then you should only start the route (and so the jms 
listener) once the service is injected. 
Christian 

2017-01-24 22:45 GMT+01:00 Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > : 

BQ_BEGIN

Yes the call is made by a component with the injected service and the service 
reference is mandatory but the initiating call to the component is from a 
remote system e.g. 

Remote system  (via Camel/JMS) > to component(s) which reference the 
newly created service 

Tim 

From: "Neil Bartlett" < [ mailto:njbartl...@gmail.com | njbartl...@gmail.com ] 
> 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Wednesday, 25 January, 2017 9:55:34 AM 

Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

Who makes the call to the newly published service? If it is a component with an 
injected service, then just

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Raymond Auge

BTW, a very nice way of handling this queuing (i.e. async) might be OSGi
promises!

- Ray

On Tue, Jan 24, 2017 at 3:39 PM, Raymond Auge <raymond.a...@liferay.com>
wrote:

>
>
> On Tue, Jan 24, 2017 at 3:23 PM, Tim Jones <tim.jo...@mccarthy.co.nz>
> wrote:
>
>> Okay let's say for example that incoming data needs to stored in separate
>> database schemas/partitions depending upon some value within the data. We
>> don't know in advance what these values are so we can't pre create the
>> schemas/partitions before server startup, so instead when a new value
>> arrives we create the database schema/partition and tables, functions,
>> assign roles etc, then create an associated JPA persistence unit +
>> dependent services.
>>
>
> I'd be very hesitant to have all this work be the result of a single
> method call. Sounds scary!
>
> I'd probably do something like:
> - identify that a schema is needed by looking at the data
> - queue schema creation up in a schema queue
> - queue up the data in data queue
> - schema queue consumer does all that setup work, or if it had already
> been done, skip it
> - once ready create a data queue consumer
> - data queue consumer notices its data in the queue and process it
>
> Just an idea!
> - Ray
>
>
>
>>
>> Tim
>>
>>
>> --
>> *From: *"Raymond Auge" <raymond.a...@liferay.com>
>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>> *Sent: *Wednesday, 25 January, 2017 12:09:17 PM
>>
>> *Subject: *Re: [osgi-dev] How to determine when a new service instance
>> hasbeen activated?
>>
>>
>>
>> On Tue, Jan 24, 2017 at 3:08 PM, Raymond Auge <raymond.a...@liferay.com>
>> wrote:
>>
>>>
>>>
>>> On Tue, Jan 24, 2017 at 3:00 PM, Tim Jones <tim.jo...@mccarthy.co.nz>
>>> wrote:
>>>
>>>> Ray can you please explain a little more what you mean by 'manifest the
>>>> schemas'? One thing I should have said is we don't know in advance of
>>>> server startup as to what schemas will be needed.
>>>>
>>>> BTW I have read http://www.coding-dude.com/wp/
>>>> java/liferay/liferay-multi-tenancy-setup-with-shards/
>>>>
>>>
>>> That article is a little dated but it's fine :)
>>>
>>> What I mean to suggest is that rather than having creation of schema be
>>> a side effect caused by some method call, it could probably be better
>>> modelled by some agent specializing in schema who once it's built a schema
>>> exposes it as an OSGi service.
>>>
>>> This way other components interested in schema can have real service
>>> dependencies on those concert services.
>>>
>>
>> auto-correct gaf: ...schema services...
>>
>>
>>>
>>> I hope that is a little more clear.
>>>
>>> However, I've been slightly confused by the implication of your
>>> statement:
>>> > we don't know in advance of server startup as to what schemas will be
>>> needed
>>>
>>> My question to that is; isn't that a function of somebody providing one
>>> or not Otherwise, I can't see how you'd magically get a schema as a result
>>> of a function call? To me that feels a little reverse. I think the schema
>>> should arrive and then others who may need it would be satisfied or not.
>>>
>>> - Ray
>>>
>>>
>>>
>>>>
>>>>
>>>> Tim
>>>>
>>>>
>>>> --
>>>> *From: *"Raymond Auge" <raymond.a...@liferay.com>
>>>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>>>> *Sent: *Wednesday, 25 January, 2017 11:20:37 AM
>>>>
>>>> *Subject: *Re: [osgi-dev] How to determine when a new service instance
>>>> hasbeen activated?
>>>>
>>>>
>>>>
>>>> On Tue, Jan 24, 2017 at 2:17 PM, Tim Jones <tim.jo...@mccarthy.co.nz>
>>>> wrote:
>>>>
>>>>> Actually the remote service still calls the same 'top level' component
>>>>> but it is this component that will make the choice as to which set of
>>>>> instance of services are ultimately exercised. At the risk of going too 
>>>>> far
>>>>> off topic but to illustrate the requirement, the application is a
>>>>> multi-tenant system that needs to

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Raymond Auge

On Tue, Jan 24, 2017 at 3:08 PM, Raymond Auge <raymond.a...@liferay.com>
wrote:

>
>
> On Tue, Jan 24, 2017 at 3:00 PM, Tim Jones <tim.jo...@mccarthy.co.nz>
> wrote:
>
>> Ray can you please explain a little more what you mean by 'manifest the
>> schemas'? One thing I should have said is we don't know in advance of
>> server startup as to what schemas will be needed.
>>
>> BTW I have read http://www.coding-dude.com/wp/
>> java/liferay/liferay-multi-tenancy-setup-with-shards/
>>
>
> That article is a little dated but it's fine :)
>
> What I mean to suggest is that rather than having creation of schema be a
> side effect caused by some method call, it could probably be better
> modelled by some agent specializing in schema who once it's built a schema
> exposes it as an OSGi service.
>
> This way other components interested in schema can have real service
> dependencies on those concert services.
>

auto-correct gaf: ...schema services...


>
> I hope that is a little more clear.
>
> However, I've been slightly confused by the implication of your statement:
> > we don't know in advance of server startup as to what schemas will be
> needed
>
> My question to that is; isn't that a function of somebody providing one or
> not Otherwise, I can't see how you'd magically get a schema as a result of
> a function call? To me that feels a little reverse. I think the schema
> should arrive and then others who may need it would be satisfied or not.
>
> - Ray
>
>
>
>>
>>
>> Tim
>>
>>
>> ------
>> *From: *"Raymond Auge" <raymond.a...@liferay.com>
>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>> *Sent: *Wednesday, 25 January, 2017 11:20:37 AM
>>
>> *Subject: *Re: [osgi-dev] How to determine when a new service instance
>> hasbeen activated?
>>
>>
>>
>> On Tue, Jan 24, 2017 at 2:17 PM, Tim Jones <tim.jo...@mccarthy.co.nz>
>> wrote:
>>
>>> Actually the remote service still calls the same 'top level' component
>>> but it is this component that will make the choice as to which set of
>>> instance of services are ultimately exercised. At the risk of going too far
>>> off topic but to illustrate the requirement, the application is a
>>> multi-tenant system that needs to be able to create and access new db
>>> schemas on the fly. I don't wont the call to create the new db schemas and
>>> the associated services to return until they have been created.
>>>
>>
>> A nice way to do this is to flip the problem on it's head and manifest
>> the schemas, once ready, as a services and have interested components
>> declare references to those services.
>>
>> - Ray
>>
>>
>>
>>> Tim
>>>
>>>
>>>
>>> --
>>> *From: *"Christian Schneider" <ch...@die-schneider.net>
>>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>>> *Sent: *Wednesday, 25 January, 2017 11:01:20 AM
>>>
>>> *Subject: *Re: [osgi-dev] How to determine when a new service instance
>>> hasbeen activated?
>>>
>>> If the call is via jms then you should only start the route (and so the
>>> jms listener) once the service is injected.
>>> Christian
>>>
>>> 2017-01-24 22:45 GMT+01:00 Tim Jones <tim.jo...@mccarthy.co.nz>:
>>>
>>>> Yes the call is made by a component with the injected service and the
>>>> service reference is mandatory but the initiating call to the component is
>>>> from a remote system e.g.
>>>>
>>>> Remote system  (via Camel/JMS) > to component(s) which
>>>> reference the newly created service
>>>>
>>>> Tim
>>>>
>>>>
>>>> --
>>>> *From: *"Neil Bartlett" <njbartl...@gmail.com>
>>>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>>>> *Sent: *Wednesday, 25 January, 2017 9:55:34 AM
>>>>
>>>> *Subject: *Re: [osgi-dev] How to determine when a new service
>>>> instancehasbeen activated?
>>>>
>>>> Who makes the call to the newly published service? If it is a component
>>>> with an injected service, then just make the service reference mandatory.
>>>> The component will then not be *able* to call the first service u

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Raymond Auge

On Tue, Jan 24, 2017 at 3:00 PM, Tim Jones <tim.jo...@mccarthy.co.nz> wrote:

> Ray can you please explain a little more what you mean by 'manifest the
> schemas'? One thing I should have said is we don't know in advance of
> server startup as to what schemas will be needed.
>
> BTW I have read http://www.coding-dude.com/wp/java/liferay/liferay-multi-
> tenancy-setup-with-shards/
>

That article is a little dated but it's fine :)

What I mean to suggest is that rather than having creation of schema be a
side effect caused by some method call, it could probably be better
modelled by some agent specializing in schema who once it's built a schema
exposes it as an OSGi service.

This way other components interested in schema can have real service
dependencies on those concert services.

I hope that is a little more clear.

However, I've been slightly confused by the implication of your statement:
> we don't know in advance of server startup as to what schemas will be
needed

My question to that is; isn't that a function of somebody providing one or
not Otherwise, I can't see how you'd magically get a schema as a result of
a function call? To me that feels a little reverse. I think the schema
should arrive and then others who may need it would be satisfied or not.

- Ray



>
>
> Tim
>
>
> --
> *From: *"Raymond Auge" <raymond.a...@liferay.com>
> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
> *Sent: *Wednesday, 25 January, 2017 11:20:37 AM
>
> *Subject: *Re: [osgi-dev] How to determine when a new service instance
> hasbeen activated?
>
>
>
> On Tue, Jan 24, 2017 at 2:17 PM, Tim Jones <tim.jo...@mccarthy.co.nz>
> wrote:
>
>> Actually the remote service still calls the same 'top level' component
>> but it is this component that will make the choice as to which set of
>> instance of services are ultimately exercised. At the risk of going too far
>> off topic but to illustrate the requirement, the application is a
>> multi-tenant system that needs to be able to create and access new db
>> schemas on the fly. I don't wont the call to create the new db schemas and
>> the associated services to return until they have been created.
>>
>
> A nice way to do this is to flip the problem on it's head and manifest the
> schemas, once ready, as a services and have interested components declare
> references to those services.
>
> - Ray
>
>
>
>> Tim
>>
>>
>>
>> --------------
>> *From: *"Christian Schneider" <ch...@die-schneider.net>
>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>> *Sent: *Wednesday, 25 January, 2017 11:01:20 AM
>>
>> *Subject: *Re: [osgi-dev] How to determine when a new service instance
>> hasbeen activated?
>>
>> If the call is via jms then you should only start the route (and so the
>> jms listener) once the service is injected.
>> Christian
>>
>> 2017-01-24 22:45 GMT+01:00 Tim Jones <tim.jo...@mccarthy.co.nz>:
>>
>>> Yes the call is made by a component with the injected service and the
>>> service reference is mandatory but the initiating call to the component is
>>> from a remote system e.g.
>>>
>>> Remote system ---- (via Camel/JMS) > to component(s) which reference
>>> the newly created service
>>>
>>> Tim
>>>
>>>
>>> --
>>> *From: *"Neil Bartlett" <njbartl...@gmail.com>
>>> *To: *"OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
>>> *Sent: *Wednesday, 25 January, 2017 9:55:34 AM
>>>
>>> *Subject: *Re: [osgi-dev] How to determine when a new service
>>> instancehasbeen activated?
>>>
>>> Who makes the call to the newly published service? If it is a component
>>> with an injected service, then just make the service reference mandatory.
>>> The component will then not be *able* to call the first service until it is
>>> actually published.
>>>
>>> Most of these timing and ordering problems disappear when you break the
>>> system down into components with injected service references. The DS
>>> runtime takes care of the underlying complexity and gives you a simple
>>> guarantee: for as long as your component is active, it can use its injected
>>> services without worrying about whether they are available yet and/or still
>>> available.
>>>
>>> Neil
>>>
>>>
>>>
>>> On 24 Jan 2017, at 20:42, Tim

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Tim Jones

Actually the remote service still calls the same 'top level' component but it 
is this component that will make the choice as to which set of instance of 
services are ultimately exercised. At the risk of going too far off topic but 
to illustrate the requirement, the application is a multi-tenant system that 
needs to be able to create and access new db schemas on the fly. I don't wont 
the call to create the new db schemas and the associated services to return 
until they have been created. 

Tim 

From: "Christian Schneider" <ch...@die-schneider.net> 
To: "OSGi Developer Mail List" <osgi-dev@mail.osgi.org> 
Sent: Wednesday, 25 January, 2017 11:01:20 AM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

If the call is via jms then you should only start the route (and so the jms 
listener) once the service is injected. 
Christian 

2017-01-24 22:45 GMT+01:00 Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > : 

Yes the call is made by a component with the injected service and the service 
reference is mandatory but the initiating call to the component is from a 
remote system e.g. 

Remote system  (via Camel/JMS) > to component(s) which reference the 
newly created service 

Tim 

From: "Neil Bartlett" < [ mailto:njbartl...@gmail.com | njbartl...@gmail.com ] 
> 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Wednesday, 25 January, 2017 9:55:34 AM 

Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

Who makes the call to the newly published service? If it is a component with an 
injected service, then just make the service reference mandatory. The component 
will then not be *able* to call the first service until it is actually 
published. 

Most of these timing and ordering problems disappear when you break the system 
down into components with injected service references. The DS runtime takes 
care of the underlying complexity and gives you a simple guarantee: for as long 
as your component is active, it can use its injected services without worrying 
about whether they are available yet and/or still available. 

Neil 

BQ_BEGIN

On 24 Jan 2017, at 20:42, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > wrote: 

Thanks Neil and Christian, 

I may be going about this the wrong way but the service is ultimately injected 
into other components as you have suggested Christian. But, I don't want to 
return until the target service has been activated (and then hopefully fairly 
quickly referenced by other services) as the programatic call to 
ConfigurationAdmin.createFactoryConfiguration() is from a remote system and the 
next remote call will be to the services that have references to this newly 
published/activated service. If the next remote call is too soon the call would 
regularly fail as the service would not have been activated yet. While I 
acknowledge the next remote call can still fail I would rather this was the 
exceptional case. 

Tim 

From: "Neil Bartlett" < [ mailto:njbartl...@gmail.com | njbartl...@gmail.com ] 
> 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Monday, 23 January, 2017 11:18:54 PM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

I agree with Christian but would add an exception to his rule… using 
ServiceTracker.waitForService() is useful when writing unit tests. The other 
options such as adding fixed-length sleeps are unreliable and seriously damage 
the performance of your test runs. 

Neil 

BQ_BEGIN

On 23 Jan 2017, at 06:26, Christian Schneider < [ 
mailto:ch...@die-schneider.net | ch...@die-schneider.net ] > wrote: 

This exactly the expected behaviour. The @Activate method allows the component 
to configure itself. The service of the component will only be published when 
the @Activate method has finished. If it would be published earlier then the 
service might be in an invalid state. 
Btw. You should avoid using waitForService. Instead override the addedService 
method of ServiceTracker and continue your initialization only when the service 
is present. Even better just inject the servcie into another @Component. 

Christian 

2017-01-22 21:14 GMT+01:00 Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > : 

BQ_BEGIN

Hi, 
I am after some advice on the following. 

In general terms the problem is if a new instance of a service is created via a 
programatic call to ConfigurationAdmin.createFactoryConfiguration(), what 
options do I have to determine that this new service instance has been 
activated considering the call to .createFactoryConfiguration() returns 
immediately. 

I have tried setting up a s

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Tim Jones

Yes the call is made by a component with the injected service and the service 
reference is mandatory but the initiating call to the component is from a 
remote system e.g. 

Remote system  (via Camel/JMS) > to component(s) which reference the 
newly created service 

Tim 



From: "Neil Bartlett" <njbartl...@gmail.com> 
To: "OSGi Developer Mail List" <osgi-dev@mail.osgi.org> 
Sent: Wednesday, 25 January, 2017 9:55:34 AM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

Who makes the call to the newly published service? If it is a component with an 
injected service, then just make the service reference mandatory. The component 
will then not be *able* to call the first service until it is actually 
published. 

Most of these timing and ordering problems disappear when you break the system 
down into components with injected service references. The DS runtime takes 
care of the underlying complexity and gives you a simple guarantee: for as long 
as your component is active, it can use its injected services without worrying 
about whether they are available yet and/or still available. 

Neil 






On 24 Jan 2017, at 20:42, Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > wrote: 

Thanks Neil and Christian, 

I may be going about this the wrong way but the service is ultimately injected 
into other components as you have suggested Christian. But, I don't want to 
return until the target service has been activated (and then hopefully fairly 
quickly referenced by other services) as the programatic call to 
ConfigurationAdmin.createFactoryConfiguration() is from a remote system and the 
next remote call will be to the services that have references to this newly 
published/activated service. If the next remote call is too soon the call would 
regularly fail as the service would not have been activated yet. While I 
acknowledge the next remote call can still fail I would rather this was the 
exceptional case. 

Tim 




From: "Neil Bartlett" < [ mailto:njbartl...@gmail.com | njbartl...@gmail.com ] 
> 
To: "OSGi Developer Mail List" < [ mailto:osgi-dev@mail.osgi.org | 
osgi-dev@mail.osgi.org ] > 
Sent: Monday, 23 January, 2017 11:18:54 PM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

I agree with Christian but would add an exception to his rule… using 
ServiceTracker.waitForService() is useful when writing unit tests. The other 
options such as adding fixed-length sleeps are unreliable and seriously damage 
the performance of your test runs. 

Neil 



BQ_BEGIN

On 23 Jan 2017, at 06:26, Christian Schneider < [ 
mailto:ch...@die-schneider.net | ch...@die-schneider.net ] > wrote: 

This exactly the expected behaviour. The @Activate method allows the component 
to configure itself. The service of the component will only be published when 
the @Activate method has finished. If it would be published earlier then the 
service might be in an invalid state. 

Btw. You should avoid using waitForService. Instead override the addedService 
method of ServiceTracker and continue your initialization only when the service 
is present. Even better just inject the servcie into another @Component. 

Christian 

2017-01-22 21:14 GMT+01:00 Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > : 

BQ_BEGIN

Hi, 
I am after some advice on the following. 

In general terms the problem is if a new instance of a service is created via a 
programatic call to ConfigurationAdmin.createFactoryConfiguration(), what 
options do I have to determine that this new service instance has been 
activated considering the call to .createFactoryConfiguration() returns 
immediately. 

I have tried setting up a service tracker with a filter for the specific 
instance of the service but I am not sure I understand the expected behavior of 
the .waitForService() method. For a small timeout period e.g. 1ms the call to 
.waitForService() returns with a null service as I would expect. For a longer 
timeout period e.g. 1000ms the call to .waitForService() returns with non null 
service and from the logs I can see that it seems to return only after the 
tracked service has returned from the @Activate method, is this the expected 
behavior? 
I also tried adding a sleep for 0.5 sec in the @Activate method of the tracked 
service and the .waitForService() still only returned after the @Activate 
method of that service had returned. Does the registration of a service have 
any dependency on its activation in the context of Declarative Services? Note 
the tracked service has @Component(immediate = true) 

Although the behavior is what I am after ie .waitForService() only seems to 
return after the tracked service has activated I am wondering if I am just 
getting lucky in this case. 
Regards, 
Tim Jones 




___

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Neil Bartlett

Who makes the call to the newly published service? If it is a component with an 
injected service, then just make the service reference mandatory. The component 
will then not be *able* to call the first service until it is actually 
published.

Most of these timing and ordering problems disappear when you break the system 
down into components with injected service references. The DS runtime takes 
care of the underlying complexity and gives you a simple guarantee: for as long 
as your component is active, it can use its injected services without worrying 
about whether they are available yet and/or still available.

Neil



> On 24 Jan 2017, at 20:42, Tim Jones <tim.jo...@mccarthy.co.nz> wrote:
> 
> Thanks Neil and Christian,
> 
> I may be going about this the wrong way but the service is ultimately 
> injected into other components as you have suggested Christian. But, I don't 
> want to return until the target service has been activated (and then 
> hopefully fairly quickly referenced by other services) as the programatic 
> call to ConfigurationAdmin.createFactoryConfiguration() is from a remote 
> system and the next remote call will be to the services that have references 
> to this newly published/activated service. If the next remote call is too 
> soon the call would regularly fail as the service would not have been 
> activated yet. While I acknowledge the next remote call can still fail I 
> would rather this was the exceptional case.
> 
> Tim
> 
> 
> 
> From: "Neil Bartlett" <njbartl...@gmail.com>
> To: "OSGi Developer Mail List" <osgi-dev@mail.osgi.org>
> Sent: Monday, 23 January, 2017 11:18:54 PM
> Subject: Re: [osgi-dev] How to determine when a new service instance has  
>   been activated?
> 
> I agree with Christian but would add an exception to his rule… using 
> ServiceTracker.waitForService() is useful when writing unit tests. The other 
> options such as adding fixed-length sleeps are unreliable and seriously 
> damage the performance of your test runs.
> 
> Neil
> 
> 
> On 23 Jan 2017, at 06:26, Christian Schneider <ch...@die-schneider.net 
> <mailto:ch...@die-schneider.net>> wrote:
> 
> This exactly the expected behaviour. The @Activate method allows the 
> component to configure itself. The service of the component will only be 
> published when the @Activate method has finished. If it would be published 
> earlier then the service might be in an invalid state.
> 
> Btw. You should avoid using waitForService. Instead override the addedService 
> method of ServiceTracker and continue your initialization only when the 
> service is present. Even better just inject the servcie into another 
> @Component.
> 
> Christian
> 
> 2017-01-22 21:14 GMT+01:00 Tim Jones <tim.jo...@mccarthy.co.nz 
> <mailto:tim.jo...@mccarthy.co.nz>>:
> Hi,
>  
> I am after some advice on the following.
> 
> In general terms the problem is if a new instance of a service is created via 
> a programatic call to ConfigurationAdmin.createFactoryConfiguration(), what 
> options do I have to determine that this new service instance has been 
> activated considering the call to  .createFactoryConfiguration() returns 
> immediately. 
> 
> I have tried setting up a service tracker with a filter for the specific 
> instance of the service but I am not sure I understand the expected behavior 
> of the .waitForService() method. For a small timeout period e.g. 1ms the call 
> to .waitForService() returns with a null service as I would expect. For a 
> longer timeout period e.g. 1000ms the call to .waitForService() returns with 
> non null service and from the logs I can see that it seems to return only 
> after the tracked service has returned from the @Activate method, is this the 
> expected behavior?
>  
> I also tried adding a sleep for 0.5 sec in the @Activate method of the 
> tracked service and the .waitForService() still only returned after the 
> @Activate method of that service had returned. Does the registration of a 
> service have any dependency on its activation in the context of Declarative 
> Services? Note the tracked service has @Component(immediate = true)
> 
> Although the behavior is what I am after ie .waitForService() only seems to 
> return after the tracked service has activated I am wondering if I am just 
> getting lucky in this case.
>  
>  
> Regards,
> Tim Jones
> 
> 
> 
> 
> ___
> OSGi Developer Mail List
> osgi-dev@mail.osgi.org <mailto:osgi-dev@mail.osgi.org>
> https://mail.osgi.org/mailman/listinfo/osgi-dev 
> <https://mail.osgi.org/mailman/listinfo/osgi-dev

Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-24 Thread Tim Jones

Thanks Neil and Christian, 

I may be going about this the wrong way but the service is ultimately injected 
into other components as you have suggested Christian. But, I don't want to 
return until the target service has been activated (and then hopefully fairly 
quickly referenced by other services) as the programatic call to 
ConfigurationAdmin.createFactoryConfiguration() is from a remote system and the 
next remote call will be to the services that have references to this newly 
published/activated service. If the next remote call is too soon the call would 
regularly fail as the service would not have been activated yet. While I 
acknowledge the next remote call can still fail I would rather this was the 
exceptional case. 

Tim 




From: "Neil Bartlett" <njbartl...@gmail.com> 
To: "OSGi Developer Mail List" <osgi-dev@mail.osgi.org> 
Sent: Monday, 23 January, 2017 11:18:54 PM 
Subject: Re: [osgi-dev] How to determine when a new service instance has been 
activated? 

I agree with Christian but would add an exception to his rule… using 
ServiceTracker.waitForService() is useful when writing unit tests. The other 
options such as adding fixed-length sleeps are unreliable and seriously damage 
the performance of your test runs. 

Neil 





On 23 Jan 2017, at 06:26, Christian Schneider < [ 
mailto:ch...@die-schneider.net | ch...@die-schneider.net ] > wrote: 

This exactly the expected behaviour. The @Activate method allows the component 
to configure itself. The service of the component will only be published when 
the @Activate method has finished. If it would be published earlier then the 
service might be in an invalid state. 

Btw. You should avoid using waitForService. Instead override the addedService 
method of ServiceTracker and continue your initialization only when the service 
is present. Even better just inject the servcie into another @Component. 

Christian 

2017-01-22 21:14 GMT+01:00 Tim Jones < [ mailto:tim.jo...@mccarthy.co.nz | 
tim.jo...@mccarthy.co.nz ] > : 

BQ_BEGIN

Hi, 
I am after some advice on the following. 

In general terms the problem is if a new instance of a service is created via a 
programatic call to ConfigurationAdmin.createFactoryConfiguration(), what 
options do I have to determine that this new service instance has been 
activated considering the call to .createFactoryConfiguration() returns 
immediately. 

I have tried setting up a service tracker with a filter for the specific 
instance of the service but I am not sure I understand the expected behavior of 
the .waitForService() method. For a small timeout period e.g. 1ms the call to 
.waitForService() returns with a null service as I would expect. For a longer 
timeout period e.g. 1000ms the call to .waitForService() returns with non null 
service and from the logs I can see that it seems to return only after the 
tracked service has returned from the @Activate method, is this the expected 
behavior? 
I also tried adding a sleep for 0.5 sec in the @Activate method of the tracked 
service and the .waitForService() still only returned after the @Activate 
method of that service had returned. Does the registration of a service have 
any dependency on its activation in the context of Declarative Services? Note 
the tracked service has @Component(immediate = true) 

Although the behavior is what I am after ie .waitForService() only seems to 
return after the tracked service has activated I am wondering if I am just 
getting lucky in this case. 
Regards, 
Tim Jones 




___ 
OSGi Developer Mail List 
[ mailto:osgi-dev@mail.osgi.org | osgi-dev@mail.osgi.org ] 
[ https://mail.osgi.org/mailman/listinfo/osgi-dev | 
https://mail.osgi.org/mailman/listinfo/osgi-dev ] 






-- 
-- 
Christian Schneider 
[ 
https://owa.talend.com/owa/redir.aspx?C=3aa4083e0c744ae1ba52bd062c5a7e46=http%3a%2f%2fwww.liquid-reality.de
 | http://www.liquid-reality.de ] 

Open Source Architect 
[ 
https://owa.talend.com/owa/redir.aspx?C=3aa4083e0c744ae1ba52bd062c5a7e46=http%3a%2f%2fwww.talend.com
 | http://www.talend.com ] 
___ 
OSGi Developer Mail List 
[ mailto:osgi-dev@mail.osgi.org | osgi-dev@mail.osgi.org ] 
https://mail.osgi.org/mailman/listinfo/osgi-dev 

BQ_END



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Re: [osgi-dev] How to determine when a new service instance has been activated?

2017-01-22 Thread Christian Schneider

This exactly the expected behaviour. The @Activate method allows the
component to configure itself. The service of the component will only be
published when the @Activate method has finished. If it would be published
earlier then the service might be in an invalid state.

Btw. You should avoid using waitForService. Instead override the
addedService method of ServiceTracker and continue your initialization only
when the service is present. Even better just inject the servcie into
another @Component.

Christian

2017-01-22 21:14 GMT+01:00 Tim Jones :

> Hi,
>
> I am after some advice on the following.
>
> In general terms the problem is if a new instance of a service is created
> via a programatic call to ConfigurationAdmin.createFactoryConfiguration(),
> what options do I have to determine that this new service instance has been
> activated considering the call to  .createFactoryConfiguration() returns
> immediately.
>
> I have tried setting up a service tracker with a filter for the specific
> instance of the service but I am not sure I understand the expected
> behavior of the .waitForService() method. For a small timeout period e.g.
> 1ms the call to .waitForService() returns with a null service as I would
> expect. For a longer timeout period e.g. 1000ms the call to
> .waitForService() returns with non null service and from the logs I can see
> that it seems to return only after the tracked service has returned from
> the @Activate method, is this the expected behavior?
>
> I also tried adding a sleep for 0.5 sec in the @Activate method of the
> tracked service and the .waitForService() still only returned after the
> @Activate method of that service had returned. Does the registration of a
> service have any dependency on its activation in the context of Declarative
> Services? Note the tracked service has @Component(immediate = true)
>
> Although the behavior is what I am after ie .waitForService() only seems
> to return after the tracked service has activated I am wondering if I am
> just getting lucky in this case.
>
>
> Regards,
> Tim Jones
>
>
>
>
> ___
> OSGi Developer Mail List
> osgi-dev@mail.osgi.org
> https://mail.osgi.org/mailman/listinfo/osgi-dev
>



-- 
-- 
Christian Schneider
http://www.liquid-reality.de


Open Source Architect
http://www.talend.com

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Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

Re: [osgi-dev] How to determine when a new service instance has been activated?

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