Registering a Managed Service

The support SAT provides for creating a Managed Service is split between two classes:

• ManagedServiceBundleActivator: This class is an abstract subclass of BaseBundleActivator and an implementer of OSGi's ManagedService interface. The class registers an instance of itself with the OSGi framework as a ManagedService.
  • A bundle that wishes to register a ManagedService creates its activator as a concrete subclass of this class.
  • The ManagedServiceBundleActivator class implements the updated(Dictionary) method and knows how to manage the object created for its configuration.
  • When called by ConfigurationAdmin the ManagedServiceBundleActivator class is capable of deciding whether the updated(Dictionary) method requires the creation of a new object, or simply the updating of an existing object. In both cases the ManagedServiceBundleActivator delegates to its advisor, an implementation of the interface IManagedServiceAdvisor that concrete subclasses are expected to create.
  • Concrete subclasses of ManagedServiceBundleActivator are required to implement the method createAdvisor() that returns an instance of the IManagedServiceAdvisor interface. An abstract implementation of this interface is provided by the class BaseManagedServiceAdvisor.
• BaseManagedServiceAdvisor: This class is an abstract implementation of the IManagedServiceAdvisor interface. Concrete subclasses must provide behavior for managing an object based on a configuration provided by ConfigurationAdmin.
• The IManagedServiceAdvisor interface is as follows:

  public interface IManagedServiceAdvisor {
  	public Object create(String, Dictionary, IBundleActivationManager);
  	public void createImportedServiceFilters(String, Dictionary, Dictionary, IBundleActivationManager);
  	public void destroy(String, Object, Dictionary , IBundleActivationManager);
  	public String[] getImportedServiceNames(String, Dictionary, Dictionary, IBundleActivationManager);
  	public String[] getOptionalImportedServiceNames(String, Dictionary, Dictionary, IBundleActivationManager);
  	public void handleAcquiredOptionalImportedService(String, Object, String, Object, IBundleActivationManager);
  	public void handleReleasedOptionalImportedService(String, Object, String, Object, IBundleActivationManager);
  	public Object update(String, Object, Dictionary, Dictionary, IBundleActivationManager);
  	public void validateConfiguration(String, Dictionary) throws ConfigurationException;
  }

• Due to the seemingly complicated nature of this interface, an example will be presented to help explain the IManagedServiceAdvisor API.

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