Utility class used to export/unexport a unicast remote object to/from the RMI system using
UnicastRemoteObject.
This utility may be used if either of the following conditions apply:
a remote object implementation cannot subclass a standard remote object implementation such
as UnicastRemoteObject because it is required to extend a different
superclass.
one desires to be able to selectively control whether or not a remote object implementation
needs to service remote callers or if it is just being used to service local calls.
Constructor Examples
This section presents examples that
show how to construct a unicast remote object exporter.
Example 1 : Default socket factories and an anonymous port
Example 2 : Specified socket factories and an anonymous port
Example 4 : Specified socket factories, port and forcible unexport
preference
Example 1: Construct an Exporter Using Default Socket Factories and
an Anonymous Port
The following code example shows how construct an exporter using default
RMI socket factories and an anonymous port.
import java.rmi.Remote;
import java.rmi.RemoteException;
import com.sas.net.rmi.RemoteObjectExporterInterface;
import com.sas.net.rmi.UnicastRemoteObjectExporter;
...
public SomeRemoteObjectImplementation ()
implements SomeRemoteInterface {
private RemoteObjectExporterInterface _rmiExporter;
public SomeRemoteObjectImplementation ()
throws RemoteException {
super();
...
// construct a unicast remote object exporter using:
// - anonymous port
// - default RMI socket factories
// - preference to forcibly unexport the remote object
boolean isForcibleUnexport = false;
_rmiExporter = new UnicastRemoteObjectExporter(
this, // the remote object to be exported
Constants.PORT_ANONYMOUS, // export remote object on an anonymous port
null, // default RMI client socket factory
null, // use default RMI server socket factory
isForcibleUnexport); // do not forcibly unexport the remote object
// export the remote object to the RMI system.
// a RemoteException will be thrown if the export fails.
Remote exportedRemoteObject = _rmiExporter.export();
}
}
Example 2: Construct an Exporter Using Specified Socket
Factories and an Anonymous Port
The following code example shows how construct an exporter
by specifying desired RMI socket factories and an anonymous port.
import java.rmi.Remote;
import java.rmi.RemoteException;
import com.sas.net.rmi.RemoteObjectExporterInterface;
import com.sas.net.rmi.UnicastRemoteObjectExporter;
import com.sas.net.ssl.SSLRMISocketFactories;
...
public SomeRemoteObjectImplementation ()
implements SomeRemoteInterface {
private RemoteObjectExporterInterface _rmiExporter;
public SomeRemoteObjectImplementation ()
throws RemoteException {
super();
...
// construct a unicast remote object exporter using:
// - anonymous port
// - specified RMI socket factories
// - preference to forcibly unexport the remote object
SSLRMISocketFactories sslRMISocketFactories =
SSLRMISocketFactories.getInstance();
Class theClass = getClass();
RMIClientSocketFactory rmiClientSocketFactory =
sslRMISocketFactories.getRMIClientSocketFactoryForClass(theClass);
RMIServerSocketFactory rmiServerSocketFactory =
sslRMISocketFactories.getRMIServerSocketFactoryForClass(theClass);
boolean isForcibleUnexport = false;
_rmiExporter = new UnicastRemoteObjectExporter(
this, // the remote object to be exported
Constants.PORT_ANONYMOUS, // export remote object on an anonymous port
rmiClientSocketFactory, // RMI client socket factory
rmiServerSocketFactory, // RMI server socket factory
isForcibleUnexport); // do not forcibly unexport the remote object
// export this remote object to the RMI system.
// RemoteException will be thrown if the export fails.
Remote exportedRemoteObject = _rmiExporter.export();
}
}
Example 3: Construct an Exporter Using Specified Socket
Factories and Port
The following code example shows how construct an exporter by specifying
desired RMI socket factories and port.
import java.rmi.Remote;
import java.rmi.RemoteException;
import com.sas.net.rmi.RemoteObjectExporterInterface;
import com.sas.net.rmi.UnicastRemoteObjectExporter;
import com.sas.net.ssl.SSLRMISocketFactories;
...
public SomeRemoteObjectImplementation ()
implements SomeRemoteInterface {
private RemoteObjectExporterInterface _rmiExporter;
public SomeRemoteObjectImplementation ()
throws RemoteException {
super();
// construct a unicast remote object exporter using:
// - specified port
// - specified RMI socket factories
// - preference to forcibly unexport the remote object
SSLRMISocketFactories sslRMISocketFactories =
SSLRMISocketFactories.getInstance();
Class theClass = getClass();
RMIClientSocketFactory rmiClientSocketFactory =
sslRMISocketFactories.getRMIClientSocketFactoryForClass(theClass);
RMIServerSocketFactory rmiServerSocketFactory =
sslRMISocketFactories.getRMIServerSocketFactoryForClass(theClass);
int portNumber = 8216;
boolean isForcibleUnexport = false;
_rmiExporter = new UnicastRemoteObjectExporter(
this, // the remote object to be exported
portNumber, // port on which to export the remote object
rmiClientSocketFactory, // RMI client socket factory
rmiServerSocketFactory, // RMI server socket factory
isForcibleUnexport); // do not forcibly unexport the remote object
// export this remote object to the RMI system.
// RemoteException will be thrown if the export fails.
Remote exportedRemoteObject = _rmiExporter.export();
}
}
Example 4: Construct an Exporter Using Specified Socket
Factories, Port and Forcible Unexport Preference
The following code example shows how
construct an exporter by specifying desired RMI socket factories, port, and forcible unexport
preference.
import java.rmi.Remote;
import java.rmi.RemoteException;
import com.sas.net.rmi.RemoteObjectExporterInterface;
import com.sas.net.rmi.UnicastRemoteObjectExporter;
import com.sas.net.ssl.SSLRMISocketFactories;
...
public SomeRemoteObjectImplementation ()
implements SomeRemoteInterface {
private RemoteObjectExporterInterface _rmiExporter;
public SomeRemoteObjectImplementation ()
throws RemoteException {
super();
// construct a unicast remote object exporter using:
// - specified port
// - specified RMI socket factories
// - preference to forcibly unexport the remote object
SSLRMISocketFactories sslRMISocketFactories =
SSLRMISocketFactories.getInstance();
Class theClass = getClass();
RMIClientSocketFactory rmiClientSocketFactory =
sslRMISocketFactories.getRMIClientSocketFactoryForClass(theClass);
RMIServerSocketFactory rmiServerSocketFactory =
sslRMISocketFactories.getRMIServerSocketFactoryForClass(theClass);
int portNumber = 8216;
boolean isForcibleUnexport = true;
_rmiExporter = new UnicastRemoteObjectExporter(
this, // the remote object to be exported
portNumber, // port on which to export the remote object
rmiClientSocketFactory, // RMI client socket factory
rmiServerSocketFactory, // RMI server socket factory
isForcibleUnexport); // do forcibly unexport the remote object
// export this remote object to the RMI system.
// RemoteException will be thrown if the export fails.
Remote exportedRemoteObject = _rmiExporter.export();
}
}
Export/Unexport Examples
This section presents code examples detailing how to
export and unexport a remote object.
The following code
example shows how to export a remote object.
import java.rmi.Remote;
import java.rmi.RemoteException;
import com.sas.net.rmi.RemoteObjectExporterInterface;
import com.sas.net.rmi.UnicastRemoteObjectExporter;
import com.sas.net.ssl.SSLRMISocketFactories;
...
public SomeRemoteObjectImplementation ()
implements SomeRemoteInterface {
private RemoteObjectExporterInterface _rmiExporter;
public SomeRemoteObjectImplementation ()
throws RemoteException {
super();
// construct a unicast remote object exporter
// using specified socket factories and an
// anonymous port
SSLRMISocketFactories sslRMISocketFactories =
SSLRMISocketFactories.getInstance();
Class theClass = getClass();
RMIClientSocketFactory rmiClientSocketFactory =
sslRMISocketFactories.getRMIClientSocketFactoryForClass(theClass);
RMIServerSocketFactory rmiServerSocketFactory =
sslRMISocketFactories.getRMIServerSocketFactoryForClass(theClass);
int portNumber = 1099;
boolean isForcibleUnexport = true;
_rmiExporter = new UnicastRemoteObjectExporter(
this,
portNumber,
rmiClientSocketFactory,
rmiServerSocketFactory,
isForcibleUnexport);
// export the remote object to the RMI system
// throws a RemoteException if unable to export the remote object.
Remote exportedRemoteObject = _rmiExporter.export();
}
}
Example 6: Unexport Unicast Remote Object
The following
code example shows how to unexport a remote object.
import java.rmi.NoSuchObjectException;
import com.sas.net.rmi.RemoteObjectExporterInterface;
import com.sas.net.rmi.UnicastRemoteObjectExporter;
...
public SomeRemoteObjectImplementation
implements SomeRemoteObjectInterface {
private RemoteObjectExporterInterface _rmiExporter;
...
public destroy () {
...
if (_rmiExporter.isExported()) {
try {
// unexport the remote object from the RMI system
// note that the remote object will be unexported
// forcibly (terminating active and refusing pending calls) if the
// preference is to forcibly unexport
boolean wasUnexported = _rmiExporter.unexport();
if (!wasUnexported) {
// if a non-forcible unexport was specified, then
// the remote object may still be servicing calls.
// forcibly unexport or try again later
}
}
catch (NoSuchObjectException) {
// log an error
}
}
}
}
UnicastRemoteObjectExporter(java.rmi.Remote remoteObject,
int portNumber,
java.rmi.server.RMIClientSocketFactory rmiClientSocketFactory,
java.rmi.server.RMIServerSocketFactory rmiServerSocketFactory,
boolean isForcibleUnexport)
Constructs an instance of an exporter which may be used to export the specified remote object
to the RMI system on a particular port using the specified client and server socket factories
and the preference to forcibly unexport the remote object.
Constructs an instance of an exporter which may be used to export the specified remote object
to the RMI system on a particular port using the specified client and server socket factories
and the preference to forcibly unexport the remote object.
Parameters:
remoteObject - The remote object that may be exported to the RMI system to create a
remote object stub.
portNumber - Port on which the object should be exported. Specify
Constants.PORT_ANONYMOUS to designate an anonymous port or a value greater
than 0 to designate a well-known port.
rmiClientSocketFactory - The client-side RMI socket factory is used to create sockets to
make calls to the remote object or null if using the default.
rmiServerSocketFactory - The server-side RMI socket factory is used to create sockets to
receive remote calls or null if using the default.
isForcibleUnexport - Specify true if the remote object should be unexported
without regard to whether or not there are any active or pending remote calls or
false if the remote object should not be unexported if there are
active or pending calls.
Exports the remote object returning the remote object's stub.
This method is called by AbstractRemoteObjectExporter.exportObject() to export a
unicast remote object stub. This method provides the concrete implementation of a template
method used to unexport a remote object stub using
UnicastRemoteObject.exportObject(Remote, int, RMIClientSocketFactory, RMIServerSocketFactory)
.
remoteObject - The remote object that may be exported to the RMI system to create a
remote object stub. Ensure that the remote object implementation correctly
implements hashCode,
equals, and toString methods to ensure correct behavior by the remote object.
portNumber - Port on which the object should be exported. Specify
Constants.PORT_ANONYMOUS to designate an anonymous port or a value greater
than 0 to designate a well-known port.
rmiClientSocketFactory - The client-side RMI socket factory is used to create sockets to
make calls to the remote object or null if using the default.
rmiServerSocketFactory - The server-side RMI socket factory is used to create sockets to
receive remote calls or null if using the default.
Returns:
Exported remote object's stub. The stub will always be non-null.
exportedRemoteObjectStub - The remote object's stub which is to be removed from the RMI
system. This is the stub which was obtained from the AbstractRemoteObjectExporter.exportObject() call.
isForcibleUnexport - true if the remote object's stub should be forcibly
removed from the RMI system without regard to whether or not there are any active
or pending calls. Specify false if the stub should not be unexported
if there are active or pending calls.
Returns:
true if the exported remote object's stub was successfully unexported
from the RMI system.
