[FELIX-5862] Bind a Service with an configurable target/placeholder in @Referance annotation

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Affects Version/s: scr-2.1.0
• Component/s: Declarative Services (SCR)
• Assignee: Unassigned
• Reporter: Stefan Bischof
• Created: 08/Jun/18 12:28
• Updated: 14/Jun/18 14:58
• Resolved: 14/Jun/18 14:58

Description

Hello,

my Component ServiceA exists one for each configuration. (foo and bar)

 

@Component(service = ServiceA.class, immediate = true)
@Designate(factory = true, ocd = ConfigA.class)
public class ServiceA {

  @ObjectClassDefinition
  public @interface ConfigA {

    String ident();
  }

  private ConfigA config;

  private void activate(ConfigA config) {
    this.config = config;
    System.out.println("ServiceA activated with ident: " + config.ident());

  }

  public String getIdent() {
    return config.ident();
  }
}

---
    "my.test.cfgservicetest.ServiceA~foo": {\
        "ident:String": "foo"\
    },\
    "my.test.cfgservicetest.ServiceA~bar": {\
        "ident:String": "bar"\
    },\

 

 

When i use a static target filter "(ident=foo)" felix could find the correct service by because the value is set in Component Configuration Properties.

@Component(service = ServiceB.class, immediate = true)
public class ServiceB {

  @Reference(target = "(ident=foo)")
  public void bindServiceA(ServiceA serviceA) {
    System.out.println("Service B -> Service A (ident): " + serviceA.getIdent());
  }
}

 

It would be great if there is a more flexible way, using a placeholder like $CCP

{serviceARefIdent} in the targetfilter. When Felix tryes bind the ServiceA to ServiceC it could lookup for the *C*omponent *C*onfiguration *P*roperties of ServiceC and replace the placeholder in the target filter before searching fore the right ServiceA.

 

@Component(service = ServiceC.class, immediate = true)
@Designate(factory = true, ocd = ConfigC.class)
public class ServiceC {

  @ObjectClassDefinition
  public @interface ConfigC {     String serviceARefIdent();   }

  private ConfigC config;


  @Reference(target = "(ident=$CCP{serviceARefIdent}

)")
  public void bindServiceA(ServiceA serviceA)

{     System.out.println("Service B -> Service A (ident): " + serviceA.getIdent());   }

}
— config
"my.test.cfgservicetest.ServiceC~foo":

{\ "serviceARefIdent:String": "foo"\  }

,\
"my.test.cfgservicetest.ServiceC~bar":

{\         "serviceARefIdent:String": "bar"\ }

{code}
 

I couldn't find information about this in the OSGi Spec.

 

Is there any way to do this at the moment?

Is there a better way to bind 2 factory-configured services to each other (without Servicetracker)?

Is there any way to add this to Felix SCR(direct or as kind of scr-plugin?)

 

It also would be nice to filter with SystemEnviromentPropertys

  @Reference(target = "(ident=$ENV{serviceARefIdent})")

 

 

 

Regards

Stefan