Interface Activator

Method Detail

• activate

  MarshalledObject<? extends Remote> activate(ActivationID id,
                                            boolean force)
                                              throws ActivationException,
                                                     UnknownObjectException,
                                                     RemoteException

  Activate the object associated with the activation identifier, id. If the activator knows the object to be active already, and force is false , the stub with a "live" reference is returned immediately to the caller; otherwise, if the activator does not know that corresponding the remote object is active, the activator uses the activation descriptor information (previously registered) to determine the group (VM) in which the object should be activated. If an ActivationInstantiator corresponding to the object's group descriptor already exists, the activator invokes the activation group's newInstance method passing it the object's id and descriptor.

  If the activation group for the object's group descriptor does not yet exist, the activator starts an ActivationInstantiator executing (by spawning a child process, for example). When the activator receives the activation group's call back (via the ActivationSystem's activeGroup method) specifying the activation group's reference, the activator can then invoke that activation instantiator's newInstance method to forward each pending activation request to the activation group and return the result (a marshalled remote object reference, a stub) to the caller.

  Note that the activator receives a "marshalled" object instead of a Remote object so that the activator does not need to load the code for that object, or participate in distributed garbage collection for that object. If the activator kept a strong reference to the remote object, the activator would then prevent the object from being garbage collected under the normal distributed garbage collection mechanism.

  Parameters:

  id - the activation identifier for the object being activated

  force - if true, the activator contacts the group to obtain the remote object's reference; if false, returning the cached value is allowed.

  Returns:

  the remote object (a stub) in a marshalled form

  Throws:

  ActivationException - if object activation fails

  UnknownObjectException - if object is unknown (not registered)

  RemoteException - if remote call fails

  Since:

  1.2