Re: [osgi-dev] Retrieving service configuration implementation in reference method

[Alain Picard via osgi-dev]

Tim,

I didn't do this here since has you might have noticed this is a factory
and the evaluation (your getRendereFor) is to determine which renderer type
to get a new instance of. We are using the pattern that you describe where
the services are just selected. But maybe it's just a piece that I'm
missing and it's a simple change.

Alain

On Fri, Aug 24, 2018 at 5:52 AM Tim Ward  wrote:

> Right, so in this case it looks like you’re running a whiteboard, is it
> possible you would be better off not using the service properties for this
> filtering? For example:
>
> @Reference(policy=DYNAMIC, cardinality=MULTIPLE)
> private final List renderers = new CopyOnWriteArrayList<>();
>
> public ZKRenderer getRendererFor(Object o) {
> return renderers.stream()
> .filter(r -> r.supports(o))
> .collect(Collectors.maxBy((a,b) ->
> a.getPriority(o).compareTo(b.getPriority(o
> .orElseThrow(() -> new IllegalArgumentException("No renderer for
> object " + o));
> }
>
> Tim
>
> On 24 Aug 2018, at 10:34, Alain Picard  wrote:
>
> They represent classes, which is why I would have like to have a Class
> annotation so I could do "tester=MyTester.class". instead of
> "tester="com.acme.mypkg.MyTester".
>
> For example I have a number of components implementing a service and as
> part of their property they define their "filter conditions" which are then
> passed on to the 3rd party library, and there are 2 types of testers, etc:
> Component(service=ZKRenderer.class, factory=ZKRenderer.CONFIG_FACTORY,
>   property= { ZKRenderer.CONFIG_STATIC_TEST +
> "=c.c.i.tester.ReferenceTree",
>   ZKRenderer.CONFIG_STATIC_TEST_PRIORITY + ":Integer=9" })
>
> If I move my ReferenceTree tester in the above case, no compiler would
> catch it and I'm just looking for pain in the future.
>
> I am not sure I grasp your approach. Here clients just ask for a renderer
> (an instance of the service) for some "object" that is passed in and an
> appropriate and "highest ranking" one is returned. So the client is never
> specifying the class string at all. Here we are providing the full class
> name so it can be loaded, hence it would be much more natural to provide a
> Class object.
>
> When we have cases where the component and reference must have to match we
> do as such:
> public static final String CONFIG_QUALIFIER =
> OsgiConstants.SERVICE_QUALIFIER + "=ReferenceList"; //$NON-NLS-1$
> public static final String CONFIG_TARGET = "(" + CONFIG_QUALIFIER +
> ")"; //$NON-NLS-1$ //$NON-NLS-2$
>
> and here the component use the 1st line in its property and the reference
> target uses the 2nd constant and that is not an issue.
>
> Alain
>
>
>
> Alain Picard
> Chief Strategy Officer
> Castor Technologies Inc
> o:514-360-7208
> m:813-787-3424
>
> pic...@castortech.com
> www.castortech.com
>
>
> On Fri, Aug 24, 2018 at 5:16 AM Tim Ward  wrote:
>
>> Do these properties “represent” classes or are they actually classes? If
>> they are just representations (which would be a good thing) then you can
>> define a static string constant representing the class which is mapped
>> internally to the correct class name (which can then change over time).
>> Clients then filter based on the string representation which will not
>> change.
>>
>> Tim
>>
>>
>> On 24 Aug 2018, at 10:07, Alain Picard  wrote:
>>
>> Tim & all,
>>
>> My immediate use case is that my components have some properties and some
>> of those represent classes (this interfaces with 3rd party libraries, I
>> would probably design it differently if I could, but it has to be
>> configuration as it is used to determine if the component is a match, much
>> like for target filters). Properties in the component annotation are
>> String[] and that forces the specification of classes as String which is
>> very bad since if the class is moved, renamed, deleted, etc, it will cause
>> no error or warning and blow up later on. And since annotations only
>> support compile time constants, you can't do a MyClass.class.getName() to
>> even get a String. My idea was since the implementation class is part of
>> the component description, if I could get a hold of it, to have a static
>> method in the class to provide this "constant".
>>
>> How can I work around the limitations of Properties as String and Java
>> compile time constants. Am I stuck to introduce a new separate annotation
>> to track this configuration?
>>
>> Alain
>>
>> Alain
>>
>>
>> On Thu, Aug 23, 2018 at 5:24 AM Tim Ward  wrote:
>>
>>> The properties visible in the Map (or ServiceReference) are the service
>>> properties. There is some overlap with configuration (services that are
>>> configurable are encouraged to publish configuration properties as service
>>> properties) but they are separate, and can be different.
>>>
>>> The only way that something becomes a service property is if it is
>>> deliberately registered as such or, for a few specific properties such as
>>> service.id and service.scope, added 

Re: [osgi-dev] Retrieving service configuration implementation in reference method

[Tim Ward via osgi-dev]

Right, so in this case it looks like you’re running a whiteboard, is it 
possible you would be better off not using the service properties for this 
filtering? For example:

@Reference(policy=DYNAMIC, cardinality=MULTIPLE)
private final List renderers = new CopyOnWriteArrayList<>();

public ZKRenderer getRendererFor(Object o) {
return renderers.stream()
.filter(r -> r.supports(o))
.collect(Collectors.maxBy((a,b) -> 
a.getPriority(o).compareTo(b.getPriority(o
.orElseThrow(() -> new IllegalArgumentException("No renderer for object 
" + o));
}

Tim

> On 24 Aug 2018, at 10:34, Alain Picard  wrote:
> 
> They represent classes, which is why I would have like to have a Class 
> annotation so I could do "tester=MyTester.class". instead of 
> "tester="com.acme.mypkg.MyTester". 
> 
> For example I have a number of components implementing a service and as part 
> of their property they define their "filter conditions" which are then passed 
> on to the 3rd party library, and there are 2 types of testers, etc:
> Component(service=ZKRenderer.class, factory=ZKRenderer.CONFIG_FACTORY,
>   property= { ZKRenderer.CONFIG_STATIC_TEST + "=c.c.i.tester.ReferenceTree", 
>   ZKRenderer.CONFIG_STATIC_TEST_PRIORITY + ":Integer=9" })
> 
> If I move my ReferenceTree tester in the above case, no compiler would catch 
> it and I'm just looking for pain in the future. 
> 
> I am not sure I grasp your approach. Here clients just ask for a renderer (an 
> instance of the service) for some "object" that is passed in and an 
> appropriate and "highest ranking" one is returned. So the client is never 
> specifying the class string at all. Here we are providing the full class name 
> so it can be loaded, hence it would be much more natural to provide a Class 
> object. 
> 
> When we have cases where the component and reference must have to match we do 
> as such:
> public static final String CONFIG_QUALIFIER = 
> OsgiConstants.SERVICE_QUALIFIER + "=ReferenceList"; //$NON-NLS-1$
> public static final String CONFIG_TARGET = "(" + CONFIG_QUALIFIER + ")"; 
> //$NON-NLS-1$ //$NON-NLS-2$
> 
> and here the component use the 1st line in its property and the reference 
> target uses the 2nd constant and that is not an issue.
> 
> Alain
> 
> 
> 
> Alain Picard
> Chief Strategy Officer
> Castor Technologies Inc
> o:514-360-7208
> m:813-787-3424
> 
> pic...@castortech.com 
> www.castortech.com 
> 
> On Fri, Aug 24, 2018 at 5:16 AM Tim Ward  > wrote:
> Do these properties “represent” classes or are they actually classes? If they 
> are just representations (which would be a good thing) then you can define a 
> static string constant representing the class which is mapped internally to 
> the correct class name (which can then change over time). Clients then filter 
> based on the string representation which will not change.
> 
> Tim
> 
> 
>> On 24 Aug 2018, at 10:07, Alain Picard > > wrote:
>> 
>> Tim & all,
>> 
>> My immediate use case is that my components have some properties and some of 
>> those represent classes (this interfaces with 3rd party libraries, I would 
>> probably design it differently if I could, but it has to be configuration as 
>> it is used to determine if the component is a match, much like for target 
>> filters). Properties in the component annotation are String[] and that 
>> forces the specification of classes as String which is very bad since if the 
>> class is moved, renamed, deleted, etc, it will cause no error or warning and 
>> blow up later on. And since annotations only support compile time constants, 
>> you can't do a MyClass.class.getName() to even get a String. My idea was 
>> since the implementation class is part of the component description, if I 
>> could get a hold of it, to have a static method in the class to provide this 
>> "constant".
>> 
>> How can I work around the limitations of Properties as String and Java 
>> compile time constants. Am I stuck to introduce a new separate annotation to 
>> track this configuration?
>> 
>> Alain
>> 
>> Alain
>> 
>> 
>> On Thu, Aug 23, 2018 at 5:24 AM Tim Ward > > wrote:
>> The properties visible in the Map (or ServiceReference) are the service 
>> properties. There is some overlap with configuration (services that are 
>> configurable are encouraged to publish configuration properties as service 
>> properties) but they are separate, and can be different.
>> 
>> The only way that something becomes a service property is if it is 
>> deliberately registered as such or, for a few specific properties such as 
>> service.id  and service.scope, added automatically by 
>> the framework. 
>> 
>> The class name of the implementation would only be added as a service 
>> property if done so deliberately, and this is typically discouraged (it 
>> leaks internal 

Re: [osgi-dev] Retrieving service configuration implementation in reference method

[Alain Picard via osgi-dev]

They represent classes, which is why I would have like to have a Class
annotation so I could do "tester=MyTester.class". instead of
"tester="com.acme.mypkg.MyTester".

For example I have a number of components implementing a service and as
part of their property they define their "filter conditions" which are then
passed on to the 3rd party library, and there are 2 types of testers, etc:
Component(service=ZKRenderer.class, factory=ZKRenderer.CONFIG_FACTORY,
  property= { ZKRenderer.CONFIG_STATIC_TEST +
"=c.c.i.tester.ReferenceTree",
  ZKRenderer.CONFIG_STATIC_TEST_PRIORITY + ":Integer=9" })

If I move my ReferenceTree tester in the above case, no compiler would
catch it and I'm just looking for pain in the future.

I am not sure I grasp your approach. Here clients just ask for a renderer
(an instance of the service) for some "object" that is passed in and an
appropriate and "highest ranking" one is returned. So the client is never
specifying the class string at all. Here we are providing the full class
name so it can be loaded, hence it would be much more natural to provide a
Class object.

When we have cases where the component and reference must have to match we
do as such:
public static final String CONFIG_QUALIFIER =
OsgiConstants.SERVICE_QUALIFIER + "=ReferenceList"; //$NON-NLS-1$
public static final String CONFIG_TARGET = "(" + CONFIG_QUALIFIER +
")"; //$NON-NLS-1$ //$NON-NLS-2$

and here the component use the 1st line in its property and the reference
target uses the 2nd constant and that is not an issue.

Alain



Alain Picard
Chief Strategy Officer
Castor Technologies Inc
o:514-360-7208
m:813-787-3424

pic...@castortech.com
www.castortech.com


On Fri, Aug 24, 2018 at 5:16 AM Tim Ward  wrote:

> Do these properties “represent” classes or are they actually classes? If
> they are just representations (which would be a good thing) then you can
> define a static string constant representing the class which is mapped
> internally to the correct class name (which can then change over time).
> Clients then filter based on the string representation which will not
> change.
>
> Tim
>
>
> On 24 Aug 2018, at 10:07, Alain Picard  wrote:
>
> Tim & all,
>
> My immediate use case is that my components have some properties and some
> of those represent classes (this interfaces with 3rd party libraries, I
> would probably design it differently if I could, but it has to be
> configuration as it is used to determine if the component is a match, much
> like for target filters). Properties in the component annotation are
> String[] and that forces the specification of classes as String which is
> very bad since if the class is moved, renamed, deleted, etc, it will cause
> no error or warning and blow up later on. And since annotations only
> support compile time constants, you can't do a MyClass.class.getName() to
> even get a String. My idea was since the implementation class is part of
> the component description, if I could get a hold of it, to have a static
> method in the class to provide this "constant".
>
> How can I work around the limitations of Properties as String and Java
> compile time constants. Am I stuck to introduce a new separate annotation
> to track this configuration?
>
> Alain
>
> Alain
>
>
> On Thu, Aug 23, 2018 at 5:24 AM Tim Ward  wrote:
>
>> The properties visible in the Map (or ServiceReference) are the service
>> properties. There is some overlap with configuration (services that are
>> configurable are encouraged to publish configuration properties as service
>> properties) but they are separate, and can be different.
>>
>> The only way that something becomes a service property is if it is
>> deliberately registered as such or, for a few specific properties such as
>> service.id and service.scope, added automatically by the framework.
>>
>> The class name of the implementation would only be added as a service
>> property if done so deliberately, and this is typically discouraged (it
>> leaks internal implementation detail and forces your internal naming to
>> become API). If you *really* care about the details of a service (and in
>> general you shouldn’t) then you should mark it with a service property that
>> you can recognise. Ideally one that is separate from the other
>> implementation details of the service.
>>
>> Best Regards,
>>
>> Tim
>>
>> > On 22 Aug 2018, at 16:53, Alain Picard via osgi-dev <
>> osgi-dev@mail.osgi.org> wrote:
>> >
>> > In a reference method, i can get the property configuration of the
>> service along with the ComponentFactory and some other optional arguments.
>> Can any of those give me a way to retrieve the implementation from the
>> configuration (i.e. the class name of the implementation) ?
>> >
>> > Thanks
>> > Alain
>> >
>> > ___
>> > OSGi Developer Mail List
>> > osgi-dev@mail.osgi.org
>> > https://mail.osgi.org/mailman/listinfo/osgi-dev
>>
>>
>

Re: [osgi-dev] Retrieving service configuration implementation in reference method

[Tim Ward via osgi-dev]

Do these properties “represent” classes or are they actually classes? If they 
are just representations (which would be a good thing) then you can define a 
static string constant representing the class which is mapped internally to the 
correct class name (which can then change over time). Clients then filter based 
on the string representation which will not change.

Tim


> On 24 Aug 2018, at 10:07, Alain Picard  wrote:
> 
> Tim & all,
> 
> My immediate use case is that my components have some properties and some of 
> those represent classes (this interfaces with 3rd party libraries, I would 
> probably design it differently if I could, but it has to be configuration as 
> it is used to determine if the component is a match, much like for target 
> filters). Properties in the component annotation are String[] and that forces 
> the specification of classes as String which is very bad since if the class 
> is moved, renamed, deleted, etc, it will cause no error or warning and blow 
> up later on. And since annotations only support compile time constants, you 
> can't do a MyClass.class.getName() to even get a String. My idea was since 
> the implementation class is part of the component description, if I could get 
> a hold of it, to have a static method in the class to provide this "constant".
> 
> How can I work around the limitations of Properties as String and Java 
> compile time constants. Am I stuck to introduce a new separate annotation to 
> track this configuration?
> 
> Alain
> 
> Alain
> 
> 
> On Thu, Aug 23, 2018 at 5:24 AM Tim Ward  > wrote:
> The properties visible in the Map (or ServiceReference) are the service 
> properties. There is some overlap with configuration (services that are 
> configurable are encouraged to publish configuration properties as service 
> properties) but they are separate, and can be different.
> 
> The only way that something becomes a service property is if it is 
> deliberately registered as such or, for a few specific properties such as 
> service.id  and service.scope, added automatically by the 
> framework. 
> 
> The class name of the implementation would only be added as a service 
> property if done so deliberately, and this is typically discouraged (it leaks 
> internal implementation detail and forces your internal naming to become 
> API). If you *really* care about the details of a service (and in general you 
> shouldn’t) then you should mark it with a service property that you can 
> recognise. Ideally one that is separate from the other implementation details 
> of the service.
> 
> Best Regards,
> 
> Tim
> 
> > On 22 Aug 2018, at 16:53, Alain Picard via osgi-dev  > > wrote:
> > 
> > In a reference method, i can get the property configuration of the service 
> > along with the ComponentFactory and some other optional arguments. Can any 
> > of those give me a way to retrieve the implementation from the 
> > configuration (i.e. the class name of the implementation) ?
> > 
> > Thanks
> > Alain
> > 
> > ___
> > OSGi Developer Mail List
> > osgi-dev@mail.osgi.org 
> > https://mail.osgi.org/mailman/listinfo/osgi-dev 
> > 
> 

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

Re: [osgi-dev] Retrieving service configuration implementation in reference method

[Alain Picard via osgi-dev]

Tim & all,

My immediate use case is that my components have some properties and some
of those represent classes (this interfaces with 3rd party libraries, I
would probably design it differently if I could, but it has to be
configuration as it is used to determine if the component is a match, much
like for target filters). Properties in the component annotation are
String[] and that forces the specification of classes as String which is
very bad since if the class is moved, renamed, deleted, etc, it will cause
no error or warning and blow up later on. And since annotations only
support compile time constants, you can't do a MyClass.class.getName() to
even get a String. My idea was since the implementation class is part of
the component description, if I could get a hold of it, to have a static
method in the class to provide this "constant".

How can I work around the limitations of Properties as String and Java
compile time constants. Am I stuck to introduce a new separate annotation
to track this configuration?

Alain

Alain


On Thu, Aug 23, 2018 at 5:24 AM Tim Ward  wrote:

> The properties visible in the Map (or ServiceReference) are the service
> properties. There is some overlap with configuration (services that are
> configurable are encouraged to publish configuration properties as service
> properties) but they are separate, and can be different.
>
> The only way that something becomes a service property is if it is
> deliberately registered as such or, for a few specific properties such as
> service.id and service.scope, added automatically by the framework.
>
> The class name of the implementation would only be added as a service
> property if done so deliberately, and this is typically discouraged (it
> leaks internal implementation detail and forces your internal naming to
> become API). If you *really* care about the details of a service (and in
> general you shouldn’t) then you should mark it with a service property that
> you can recognise. Ideally one that is separate from the other
> implementation details of the service.
>
> Best Regards,
>
> Tim
>
> > On 22 Aug 2018, at 16:53, Alain Picard via osgi-dev <
> osgi-dev@mail.osgi.org> wrote:
> >
> > In a reference method, i can get the property configuration of the
> service along with the ComponentFactory and some other optional arguments.
> Can any of those give me a way to retrieve the implementation from the
> configuration (i.e. the class name of the implementation) ?
> >
> > Thanks
> > Alain
> >
> > ___
> > OSGi Developer Mail List
> > osgi-dev@mail.osgi.org
> > https://mail.osgi.org/mailman/listinfo/osgi-dev
>
>
___
OSGi Developer Mail List
osgi-dev@mail.osgi.org
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