java.rmi.activation
Class Activatable

java.lang.Object
  java.rmi.server.RemoteObject
      java.rmi.server.RemoteServer
          java.rmi.activation.Activatable

All Implemented Interfaces:

Serializable, Remote

public abstract class Activatable
extends RemoteServer

The Activatable class provides support for remote objects that require persistent access over time and that can be activated by the system.

For the constructors and static exportObject methods, the stub for a remote object being exported is obtained as described in UnicastRemoteObject.

Since:

1.2

See Also:

Serialized Form

Field Summary

Fields inherited from class java.rmi.server.RemoteObject

ref

Constructor Summary

protected	Activatable(ActivationID id, int port) Constructor used to activate/export the object on a specified port.
protected	Activatable(ActivationID id, int port, RMIClientSocketFactory csf, RMIServerSocketFactory ssf) Constructor used to activate/export the object on a specified port.
protected	Activatable(String location, MarshalledObject data, boolean restart, int port) Constructor used to register and export the object on a specified port (an anonymous port is chosen if port=0) .
protected	Activatable(String location, MarshalledObject data, boolean restart, int port, RMIClientSocketFactory csf, RMIServerSocketFactory ssf) Constructor used to register and export the object on a specified port (an anonymous port is chosen if port=0) .

Method Summary

static Remote	exportObject(Remote obj, ActivationID id, int port) Export the activatable remote object to the RMI runtime to make the object available to receive incoming calls.
static Remote	exportObject(Remote obj, ActivationID id, int port, RMIClientSocketFactory csf, RMIServerSocketFactory ssf) Export the activatable remote object to the RMI runtime to make the object available to receive incoming calls.
static ActivationID	exportObject(Remote obj, String location, MarshalledObject data, boolean restart, int port) This exportObject method may be invoked explicitly by an "activatable" object, that does not extend the Activatable class, in order to both a) register the object's activation descriptor, constructed from the supplied location, and data, with the activation system (so the object can be activated), and b) export the remote object, obj, on a specific port (if port=0, then an anonymous port is chosen).
static ActivationID	exportObject(Remote obj, String location, MarshalledObject data, boolean restart, int port, RMIClientSocketFactory csf, RMIServerSocketFactory ssf) This exportObject method may be invoked explicitly by an "activatable" object, that does not extend the Activatable class, in order to both a) register the object's activation descriptor, constructed from the supplied location, and data, with the activation system (so the object can be activated), and b) export the remote object, obj, on a specific port (if port=0, then an anonymous port is chosen).
protected ActivationID	getID() Returns the object's activation identifier.
static boolean	inactive(ActivationID id) Informs the system that the object with the corresponding activation id is currently inactive.
static Remote	register(ActivationDesc desc) Register an object descriptor for an activatable remote object so that is can be activated on demand.
static boolean	unexportObject(Remote obj, boolean force) Remove the remote object, obj, from the RMI runtime.
static void	unregister(ActivationID id) Revokes previous registration for the activation descriptor associated with id.

Methods inherited from class java.rmi.server.RemoteServer

getClientHost, getLog, setLog

Methods inherited from class java.rmi.server.RemoteObject

equals, getRef, hashCode, toString, toStub

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Activatable

protected Activatable(String location,
                      MarshalledObject data,
                      boolean restart,
                      int port)
               throws ActivationException,
                      RemoteException

Constructor used to register and export the object on a specified port (an anonymous port is chosen if port=0) . A concrete subclass of this class must call this constructor to register and export the object during initial construction. As a side-effect of activatable object construction, the remote object is both "registered" with the activation system and "exported" (on an anonymous port if port=0) to the RMI runtime so that it is available to accept incoming calls from clients.

Parameters:

location - the location for classes for this object

data - the object's initialization data

port - the port on which the object is exported (an anonymous port is used if port=0)

restart - if true, the object is restarted (reactivated) when either the activator is restarted or the object's activation group is restarted after an unexpected crash; if false, the object is only activated on demand. Specifying restart to be true does not force an initial immediate activation of a newly registered object; initial activation is lazy.

Throws:

ActivationException - if object registration fails.

RemoteException - if either of the following fails: a) registering the object with the activation system or b) exporting the object to the RMI runtime.

Since:

1.2

Activatable

protected Activatable(String location,
                      MarshalledObject data,
                      boolean restart,
                      int port,
                      RMIClientSocketFactory csf,
                      RMIServerSocketFactory ssf)
               throws ActivationException,
                      RemoteException

Constructor used to register and export the object on a specified port (an anonymous port is chosen if port=0) .

A concrete subclass of this class must call this constructor to register and export the object during initial construction. As a side-effect of activatable object construction, the remote object is both "registered" with the activation system and "exported" (on an anonymous port if port=0) to the RMI runtime so that it is available to accept incoming calls from clients.

Parameters:

location - the location for classes for this object

data - the object's initialization data

restart - if true, the object is restarted (reactivated) when either the activator is restarted or the object's activation group is restarted after an unexpected crash; if false, the object is only activated on demand. Specifying restart to be true does not force an initial immediate activation of a newly registered object; initial activation is lazy.

port - the port on which the object is exported (an anonymous port is used if port=0)

csf - the client-side socket factory for making calls to the remote object

ssf - the server-side socket factory for receiving remote calls

Throws:

ActivationException - if object registration fails.

RemoteException - if either of the following fails: a) registering the object with the activation system or b) exporting the object to the RMI runtime.

Since:

1.2

Activatable

protected Activatable(ActivationID id,
                      int port)
               throws RemoteException

Constructor used to activate/export the object on a specified port. An "activatable" remote object must have a constructor that takes two arguments:

• the object's activation identifier (ActivationID), and
• the object's initialization data (a MarshalledObject).

A concrete subclass of this class must call this constructor when it is activated via the two parameter constructor described above. As a side-effect of construction, the remote object is "exported" to the RMI runtime (on the specified port) and is available to accept incoming calls from clients.

Parameters:

id - activation identifier for the object

port - the port number on which the object is exported

Throws:

RemoteException - if exporting the object to the RMI runtime fails

Since:

1.2

Activatable

protected Activatable(ActivationID id,
                      int port,
                      RMIClientSocketFactory csf,
                      RMIServerSocketFactory ssf)
               throws RemoteException

Constructor used to activate/export the object on a specified port. An "activatable" remote object must have a constructor that takes two arguments:

• the object's activation identifier (ActivationID), and
• the object's initialization data (a MarshalledObject).

A concrete subclass of this class must call this constructor when it is activated via the two parameter constructor described above. As a side-effect of construction, the remote object is "exported" to the RMI runtime (on the specified port) and is available to accept incoming calls from clients.

Parameters:

id - activation identifier for the object

port - the port number on which the object is exported

csf - the client-side socket factory for making calls to the remote object

ssf - the server-side socket factory for receiving remote calls

Throws:

RemoteException - if exporting the object to the RMI runtime fails

Since:

1.2

Method Detail

getID

protected ActivationID getID()

Returns the object's activation identifier. The method is protected so that only subclasses can obtain an object's identifier.

Returns:

the object's activation identifier

Since:

1.2

register

public static Remote register(ActivationDesc desc)
                       throws UnknownGroupException,
                              ActivationException,
                              RemoteException

Register an object descriptor for an activatable remote object so that is can be activated on demand.

Parameters:

desc - the object's descriptor

Returns:

the stub for the activatable remote object

Throws:

UnknownGroupException - if group id in desc is not registered with the activation system

ActivationException - if activation system is not running

RemoteException - if remote call fails

Since:

1.2

inactive

public static boolean inactive(ActivationID id)
                        throws UnknownObjectException,
                               ActivationException,
                               RemoteException

Informs the system that the object with the corresponding activation id is currently inactive. If the object is currently active, the object is "unexported" from the RMI runtime (only if there are no pending or in-progress calls) so the that it can no longer receive incoming calls. This call informs this VM's ActivationGroup that the object is inactive, that, in turn, informs its ActivationMonitor. If this call completes successfully, a subsequent activate request to the activator will cause the object to reactivate. The operation may still succeed if the object is considered active but has already unexported itself.

Parameters:

id - the object's activation identifier

Returns:

true if the operation succeeds (the operation will succeed if the object in currently known to be active and is either already unexported or is currently exported and has no pending/executing calls); false is returned if the object has pending/executing calls in which case it cannot be deactivated

Throws:

UnknownObjectException - if object is not known (it may already be inactive)

ActivationException - if group is not active

RemoteException - if call informing monitor fails

Since:

1.2

unregister

public static void unregister(ActivationID id)
                       throws UnknownObjectException,
                              ActivationException,
                              RemoteException

Revokes previous registration for the activation descriptor associated with id. An object can no longer be activated via that id.

Parameters:

id - the object's activation identifier

Throws:

UnknownObjectException - if object (id) is unknown

ActivationException - if activation system is not running

RemoteException - if remote call to activation system fails

Since:

1.2

exportObject

public static ActivationID exportObject(Remote obj,
                                        String location,
                                        MarshalledObject data,
                                        boolean restart,
                                        int port)
                                 throws ActivationException,
                                        RemoteException

This exportObject method may be invoked explicitly by an "activatable" object, that does not extend the Activatable class, in order to both a) register the object's activation descriptor, constructed from the supplied location, and data, with the activation system (so the object can be activated), and b) export the remote object, obj, on a specific port (if port=0, then an anonymous port is chosen). Once the object is exported, it can receive incoming RMI calls.

This method does not need to be called if obj extends Activatable, since the first constructor calls this method.

Parameters:

obj - the object being exported

location - the object's code location

data - the object's bootstrapping data

restart - if true, the object is restarted (reactivated) when either the activator is restarted or the object's activation group is restarted after an unexpected crash; if false, the object is only activated on demand. Specifying restart to be true does not force an initial immediate activation of a newly registered object; initial activation is lazy.

port - the port on which the object is exported (an anonymous port is used if port=0)

Returns:

the activation identifier obtained from registering the descriptor, desc, with the activation system the wrong group

Throws:

ActivationException - if activation group is not active

RemoteException - if object registration or export fails

Since:

1.2

exportObject

public static ActivationID exportObject(Remote obj,
                                        String location,
                                        MarshalledObject data,
                                        boolean restart,
                                        int port,
                                        RMIClientSocketFactory csf,
                                        RMIServerSocketFactory ssf)
                                 throws ActivationException,
                                        RemoteException

This exportObject method may be invoked explicitly by an "activatable" object, that does not extend the Activatable class, in order to both a) register the object's activation descriptor, constructed from the supplied location, and data, with the activation system (so the object can be activated), and b) export the remote object, obj, on a specific port (if port=0, then an anonymous port is chosen). Once the object is exported, it can receive incoming RMI calls.

This method does not need to be called if obj extends Activatable, since the first constructor calls this method.

Parameters:

obj - the object being exported

location - the object's code location

data - the object's bootstrapping data

restart - if true, the object is restarted (reactivated) when either the activator is restarted or the object's activation group is restarted after an unexpected crash; if false, the object is only activated on demand. Specifying restart to be true does not force an initial immediate activation of a newly registered object; initial activation is lazy.

port - the port on which the object is exported (an anonymous port is used if port=0)

csf - the client-side socket factory for making calls to the remote object

ssf - the server-side socket factory for receiving remote calls

Returns:

the activation identifier obtained from registering the descriptor, desc, with the activation system the wrong group

Throws:

ActivationException - if activation group is not active

RemoteException - if object registration or export fails

Since:

1.2

exportObject

public static Remote exportObject(Remote obj,
                                  ActivationID id,
                                  int port)
                           throws RemoteException

Export the activatable remote object to the RMI runtime to make the object available to receive incoming calls. The object is exported on an anonymous port, if port is zero.

During activation, this exportObject method should be invoked explicitly by an "activatable" object, that does not extend the Activatable class. There is no need for objects that do extend the Activatable class to invoke this method directly; this method is called by the second constructor above (which a subclass should invoke from its special activation constructor).

Parameters:

obj - the remote object implementation

id - the object's activation identifier

port - the port on which the object is exported (an anonymous port is used if port=0)

Returns:

the stub for the activatable remote object

Throws:

RemoteException - if object export fails

Since:

1.2

exportObject

public static Remote exportObject(Remote obj,
                                  ActivationID id,
                                  int port,
                                  RMIClientSocketFactory csf,
                                  RMIServerSocketFactory ssf)
                           throws RemoteException

Export the activatable remote object to the RMI runtime to make the object available to receive incoming calls. The object is exported on an anonymous port, if port is zero.

During activation, this exportObject method should be invoked explicitly by an "activatable" object, that does not extend the Activatable class. There is no need for objects that do extend the Activatable class to invoke this method directly; this method is called by the second constructor above (which a subclass should invoke from its special activation constructor).

Parameters:

obj - the remote object implementation

id - the object's activation identifier

port - the port on which the object is exported (an anonymous port is used if port=0)

csf - the client-side socket factory for making calls to the remote object

ssf - the server-side socket factory for receiving remote calls

Returns:

the stub for the activatable remote object

Throws:

RemoteException - if object export fails

Since:

1.2

unexportObject

public static boolean unexportObject(Remote obj,
                                     boolean force)
                              throws NoSuchObjectException

Remove the remote object, obj, from the RMI runtime. If successful, the object can no longer accept incoming RMI calls. If the force parameter is true, the object is forcibly unexported even if there are pending calls to the remote object or the remote object still has calls in progress. If the force parameter is false, the object is only unexported if there are no pending or in progress calls to the object.

Parameters:

obj - the remote object to be unexported

force - if true, unexports the object even if there are pending or in-progress calls; if false, only unexports the object if there are no pending or in-progress calls

Returns:

true if operation is successful, false otherwise

Throws:

NoSuchObjectException - if the remote object is not currently exported

Since:

1.2