java.rmi.server
class UnicastRemoteObject

java.lang.Object java.rmi.server.RemoteObject java.rmi.server.RemoteServer java.rmi.server.UnicastRemoteObject

All Implemented Interfaces:

Serializable, Remote

Direct Known Subclasses:

ActivationGroup

public class UnicastRemoteObject
extends RemoteServer

Used for exporting a remote object with JRMP and obtaining a stub that communicates to the remote object.

For the constructors and static exportObject methods below, the stub for a remote object being exported is obtained as follows:

• If the remote object is exported using the {@link #exportObject(Remote) UnicastRemoteObject.exportObject(Remote)} method, a stub class (typically pregenerated from the remote object's class using the rmic tool) is loaded and an instance of that stub class is constructed as follows.
  • A "root class" is determined as follows: if the remote object's class directly implements an interface that extends {@link Remote}, then the remote object's class is the root class; otherwise, the root class is the most derived superclass of the remote object's class that directly implements an interface that extends Remote.
  • The name of the stub class to load is determined by concatenating the binary name of the root class with the suffix "_Stub".
  • The stub class is loaded by name using the class loader of the root class. The stub class must extend {@link RemoteStub} and must have a public constructor that has one parameter, of type {@link RemoteRef}.
  • Finally, an instance of the stub class is constructed with a {@link RemoteRef}.
• If the appropriate stub class could not be found, or the stub class could not be loaded, or a problem occurs creating the stub instance, a {@link StubNotFoundException} is thrown.

• For all other means of exporting:
  • If the remote object's stub class (as defined above) could not be loaded or the system property java.rmi.server.ignoreStubClasses is set to "true" (case insensitive), a {@link java.lang.reflect.Proxy} instance is constructed with the following properties:
    • The proxy's class is defined by the class loader of the remote object's class.
    • The proxy implements all the remote interfaces implemented by the remote object's class.
    • The proxy's invocation handler is a {@link RemoteObjectInvocationHandler} instance constructed with a {@link RemoteRef}.
    • If the proxy could not be created, a {@link StubNotFoundException} will be thrown.

  • Otherwise, an instance of the remote object's stub class (as described above) is used as the stub.

UnicastRemoteObject

protected UnicastRemoteObject()
                       throws RemoteException

Creates and exports a new UnicastRemoteObject object using an anonymous port.

Throws:

RemoteException - if failed to export object

UnicastRemoteObject

protected UnicastRemoteObject(int port)
                       throws RemoteException

Creates and exports a new UnicastRemoteObject object using the particular supplied port.

Parameters:

port - the port number on which the remote object receives calls (if port is zero, an anonymous port is chosen)

Throws:

RemoteException - if failed to export object

UnicastRemoteObject

protected UnicastRemoteObject(int port,
                              RMIClientSocketFactory csf,
                              RMIServerSocketFactory ssf)
                       throws RemoteException

Creates and exports a new UnicastRemoteObject object using the particular supplied port and socket factories.

Parameters:

port - the port number on which the remote object receives calls (if port is zero, an anonymous port is chosen)

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 failed to export object

clone

public Object clone()
             throws CloneNotSupportedException

Returns a clone of the remote object that is distinct from the original.

Overrides:

clone in class Object

Returns:

the new remote object

Throws:

CloneNotSupportedException - if clone failed due to a RemoteException.

exportObject

public static RemoteStub exportObject(Remote obj)
                               throws RemoteException

Exports the remote object to make it available to receive incoming calls using an anonymous port.

Parameters:

obj - the remote object to be exported

Returns:

remote object stub

Throws:

RemoteException - if export fails

exportObject

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

Exports the remote object to make it available to receive incoming calls, using the particular supplied port.

Parameters:

obj - the remote object to be exported

port - the port to export the object on

Returns:

remote object stub

Throws:

RemoteException - if export fails

exportObject

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

Exports the remote object to make it available to receive incoming calls, using a transport specified by the given socket factory.

Parameters:

obj - the remote object to be exported

port - the port to export the object on

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

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

Returns:

remote object stub

Throws:

RemoteException - if export fails

unexportObject

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

Removes 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