First of all, thanks Clement and Richard for you explainations. What I understand :
By looking at iPojo sources, if I want to use this feature, I must publish an implementation of the interface org.apache.felix.ipojo.ContextSource in the service registry with a service property source.name="foo". The value "foo", is in fact the name of the context in the composite declaration : context-source="global:foo" With that, I can refer to any property inside the context in my LDAP filter. So that, if I change a value in the context all LDAP filter are recomputed automatically. Is my understanding correct ? Thanks again. Regards, David -----Message d'origine----- De : Richard S. Hall [mailto:[email protected]] Envoyé : mercredi 24 novembre 2010 16:49 À : [email protected] Objet : Re: iPojo context-awareness On 11/24/10 9:17, Clement Escoffier wrote: > Hi, > > > On 24.11.10 13:27, "Gay David (Annecy)"<[email protected]> wrote: > >> Hi all, >> >> >> >> While looking at some documents about iPojo composition, I've see that >> there is a notion of "context-source". >> >> >> >> For example : >> >> * this presentation at page 91 : >> http://felix.apache.org/site/presentations.data/ipojo-berlin-20080611.pd >> f >> >> * this presentation at page 43 : >> http://felix.apache.org/site/article-presentations.data/iPOJO-Defense-FI >> NAL.pdf >> >> >> >> In the iPojo API, I've also see this interface : >> http://felix.apache.org/ipojo/api/1.6.0/org/apache/felix/ipojo/ContextSo >> urce.html >> >> And in the composite documentation here : >> http://felix.apache.org/site/ipojo-composition-tutorial.html , there is >> nothing about it, just a word in the conclusion that say that >> context-awareness will be addressed shortly (as other topics) >> >> >> >> While composite are very clear to me (BTW this is an fantastic feature, >> thanks), I'm not sure I understand what's really the context-source and >> context awareness. >> >> Can someone provides me more info / links / samples about this ? > The context-awareness was made to allow composition to evolve according to > a context (I.e. When the context changes, the composition is > re-evaluated). This is a little bit experimental in the sense that this > was never really used in production (as far as I know). > > The idea is kind of simple. You define context-sources providing the > context and publishing the changes. Then, the compositions are expressed > in term of the context by configuring 'context-aware-filters'. > > I will add ASAP an example of the context-awareness on the composition > tutorial to make this topic clearer. To be a little more concrete (although details may be out of date)... A context source is just something that supplies name/value pairs at run time. A composition with a context source can have its filters written in terms of properties from the context source. For example, assume you have a context source that provides the user's current location. Then when you specify a sub-service in a composite, you can reference the user's current location in its filter, e.g.: <composite name="foo"> ... <sub-service context-source="global:user-context-source" action="instantiate" specification="org.foo.Printer" filter="(location=${user.location})" /> ... </composite> In this case, the global context source "user-context-source" is used to determine the user's current location, which is used to track printer services in the same location as the user. -> richard > Regards, > > Clement > > PS: As I'm pretty sure you can read French, you can check: > http://tel.archives-ouvertes.fr/tel-00347935/en/ (pages 129 to 131) > > > >> >> >> Thanks for your help. >> >> David G. >> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
