Aha, I just saw what FELIX-4136 is all about... /Bengt
2013/10/2 Bengt Rodehav <[email protected]> > Interesting. Do you think it would also be possible to do an > all-or-nothing approach? E g if I want to require A and B, I could check if > both A and B are available. If not, I would make the list empty thus making > my instance invalid? Or can I just say that the dependency is unresolved > without having to change the list? > > BTW I did experiment a little with dynamically changing the "optionable" > property of the requires dependency using the dependency manager. I never > did get that to work. It always stayed at the same value it got through the > Requires annotation. Is that as designed or a bug? > > I currently did a workaround using the life cycle controller as adviced by > Richard. Whenever anything changes that could affect the validity of the > instance I recalculate the life cycle controller value to reflect that. For > instance if the list of dependencies change I recalculate and check if all > my required services are in the list. If not I set the controller value to > false. > > It works but the code is not very nice and easy to understand. It'll have > to do for now. > > Clement, is the 1.10.x version released? I'm on a pretty old version and > should probably upgrade. Also, is there any documentation regarding the > interceptors you mentioned? > > /Bengt > > > 2013/10/2 Clement Escoffier <[email protected]> > >> Hi, >> >> Not sure it would meet your requirements, but in the 1.10.x, we added >> service dependency interceptors. Interceptors are external entities >> involved in the service resolution. We have 3 types on interceptors: >> >> - tracking interceptors allow hiding services, or selecting the set of >> services seen by the service dependency (the LDAP filter is a tracking >> interceptor) >> - ranking interceptors can change the order of the services (the >> comparator is a ranking interceptor) >> - binding interceptors can change the injected service objects (to be >> used with caution ;-)) >> >> You can, without too much effort, write an interceptor that will shape >> the processor list as you want. >> >> As said above, interceptors are external entities. Actually, they are >> services with a special 'target' property indicating in which dependencies >> they want to be involved. So, an interceptor can select one very specific >> dependency, all dependencies of an instance, all dependencies targeting a >> specific interface… >> >> Unfortunately, there is a long overdue issue about interceptors: >> FELIX-4136 Document service dependency interceptors. >> >> Best regards, >> >> Clement >> >> >> On 2 oct. 2013, at 15:57, Bengt Rodehav <[email protected]> wrote: >> >> > Thanks for your reply Richard. >> > >> > I am using a lifecycle controller already to make it possible to >> > enable/disable my services via a GUI. I'll see if I can use it for this >> > purpose. >> > >> > I've also tried the following approach: Keep track of all possible >> services >> > that expose the interface I'm intererested in as follows: >> > >> > @Requires(optional = true) >> > private IOrchestrationProcessor[] mProcessors; >> > >> > In runtime, when my service is being activated (prior to creating the >> camel >> > route) I check to see if all required processors exist, if not I throw >> an >> > exception. Unfortunately I have no control of in what order the services >> > will be activated so its hard to ever get the camel route created this >> way. >> > A lot of the time a "required" services is activated a bit later. >> > >> > /Bengt >> > >> > >> > >> > 2013/10/2 Richard S. Hall <[email protected]> >> > >> >> >> >> On 10/2/13 08:42 , Bengt Rodehav wrote: >> >> >> >>> I'm creating a dynamic processing component using iPOJO and Camel. The >> >>> idea >> >>> is to dynamically specify (via config admin) a number of processor >> id's. >> >>> In >> >>> runtime I want to find the matching processors (the processors are >> Camel >> >>> processors published as OSGi services) with the correct id. >> >>> >> >>> E g if I specify a list of services to {A,B} (FileInstall recognizes >> this >> >>> as a list). I want to require those services in order for my iPojo >> >>> instance >> >>> to become valid. It was much harder than I thought. >> >>> >> >>> I've tried something like: >> >>> >> >>> @Property(name = "processors", mandatory = false, value = "") >> >>> public void setProcessors(String[] theProcessorIds) { >> >>> mProcessorIds = theProcessorIds; >> >>> updateProcessorFilter(); >> >>> } >> >>> >> >>> @Requires >> >>> private Processor[] mProcessors; >> >>> >> >>> The idea is that whenever the configuration property "processors" is >> >>> updated, I dynamically update the ldap filter on the dependency >> >>> mProcessors. I've used this approach before and it has worked when >> using a >> >>> single dependency (not an array). >> >>> >> >>> The problem is that I want to specifically require each specified >> >>> processor. In the example above, I require one processor with id=A >> AND one >> >>> processor with id=B. It's not enough with anyone of them since I want >> to >> >>> invoke them one after another. >> >>> >> >>> Can I use a filter for this? I've been thinking of something like >> this: >> >>> >> >>> (|(processorId=A)(processorId=**B)) >> >>> >> >>> This would match both my processors but if one of them were missing my >> >>> instance would still become valid which I don't want. >> >>> >> >> >> >> I don't think there is anyway to do what you want. This is essentially >> an >> >> "N cardinality" requirement, where you want to say that you require >> >> specifically N of something. Such requirements had been discussed over >> the >> >> years for Service Binder, Declarative Services, etc., but we could >> never >> >> agree on their usefulness or how to do them, so we just left it as it >> is >> >> now (i.e., optional, at least one...). >> >> >> >> Other than adding some sort of threshold to service dependencies, I >> don't >> >> see this happening. You could potentially create an iPOJO lifecycle >> >> controller that would keep your component invalid until it matched the >> >> required number of services (if you can get this information in the >> >> handler)...or perhaps write/extend the service dependency handler. >> >> >> >> -> richard >> >> >> >> >> >>> /Bengt >> >>> >> >>> >> >> >> >> >> ------------------------------**------------------------------**--------- >> >> To unsubscribe, e-mail: users-unsubscribe@felix.**apache.org< >> [email protected]> >> >> For additional commands, e-mail: [email protected] >> >> >> >> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> >> >
