How to use org.qi4j.api.service.qualifier

  @Override
  public Specification<ServiceReference<?>> qualifier( Tagged tagged )
  {
    return ServiceQualifier.withTags( tagged.value() );
  }
}

  @Override
  public <T> Specification<ServiceReference<?>> qualifier( IdentifiedBy identifiedBy )
  {
    return ServiceQualifier.withId( identifiedBy.value() );
  }
}

  public boolean hasTags( String... aTags )
  {
    for( String tag : aTags )
    {
      if( !hasTag( tag ) )
      {
        return false;
      }
    }

    return true;
  }
}

  abstract class RdfQueryParserFactoryMixin
    implements RdfQueryParserFactory
  {
    @Structure
    private Qi4jSPI spi;
    @Service
    @Tagged( ValueSerialization.Formats.JSON )
    private ValueSerializer valueSerializer;

    @Override
    public RdfQueryParser newQueryParser( QueryLanguage language )
    {
      if( language.equals( QueryLanguage.SPARQL ) )
      {
        return new RdfQueryParserImpl( spi, valueSerializer );
      }
      throw new UnsupportedLanguageException( language );
    }
  }
}

  @Override
  @SuppressWarnings( {"raw", "unchecked"} )
  public boolean satisfiedBy( ServiceReference<?> service )
  {
    for( Class metaInfoType : hasMetaInfo.value() )
    {
      Object metaInfo = service.metaInfo( metaInfoType );
      if( hasMetaInfo.anded() )
      {
        if( metaInfo == null )
        {
          return false;
        }
      }
      else
      {
        if( metaInfo != null )
        {
          return true;
        }
      }
    }
    return false;
  }
};

  @Override
  public <T> Specification<ServiceReference<?>> qualifier( Available active )
  {
    return ServiceQualifier.whereAvailable();
  }
}

  @Override
  public <T> Specification<ServiceReference<?>> qualifier( Active active )
  {
    return ServiceQualifier.whereActive();
  }
}

  @Override
  public boolean satisfiedBy( ServiceReference<?> service )
  {
    ServiceTags serviceTags = service.metaInfo( ServiceTags.class );
    return serviceTags != null && serviceTags.hasTags( tags );
  }
};

@Override
@SuppressWarnings( { "raw", "unchecked" } )
public T importService( ImportedServiceDescriptor serviceDescriptor )
  throws ServiceImporterException
{
  Specification<ServiceReference<?>> selector = serviceDescriptor.metaInfo( Specification.class );
  Class serviceType = Iterables.first( serviceDescriptor.types() );
  Iterable<ServiceReference<T>> services = locator.findServices( serviceType );
  List<ServiceReference<T>> filteredServices = new ArrayList<>();
  for( ServiceReference<T> service : services )
  {
    Specification selector1 = service.metaInfo( Specification.class );
    if( selector1 != null && selector1 == selector )
    {
      continue;
    }
    filteredServices.add( service );
  }
  T service = ServiceQualifier.firstService( selector, filteredServices );
  if( service == null )
  {
    throw new ServiceImporterException( "Could not find any service to import that matches the given specification for " + serviceDescriptor
      .identity() );
  }
  return service;
}

@Tagged( ValueSerialization.Formats.JSON )
private ValueSerializer valueSerializer;

  private <C, V extends Identity> V readConfig( UnitOfWork uow,
                         Class<C> compositeType,
                         Class<V> configType,
                         String identity,
                         String format,
                         String extension
  )
  {
    for( ServiceReference<ValueSerialization> serializerRef : valueSerialization )
    {
      ServiceTags serviceTags = serializerRef.metaInfo( ServiceTags.class );
      if( serviceTags.hasTag( format ) )
      {
        String resourceName = identity + extension;
        InputStream asStream = getResource( compositeType, resourceName );
        if( asStream != null )
        {
          V configObject = serializerRef.get().deserialize( configType, asStream );
          return uow.toEntity( configType, configObject );
        }
      }
    }
    return null;
  }
}

@Tagged( ValueSerialization.Formats.JSON )
private ValueSerializer valueSerializer;

@Tagged( ValueSerialization.Formats.JSON )
private ValueDeserializer valueDeserializer;