PortableRemoteObject (GNU Classpath 0.94-pre Documentation)

An utility class for RMI/IDL server side object implementations. Server side implementation objects may inherit from this class, but this is not mandatory, as the needed methds are static. Server side implementations may choose to inherit from {@link ObjectImpl} or {@link Servant} instead.

The functionality of methods in this class is forwarded to the enclosed PortableRemoteObjectDelegate. This delegate can be altered by setting the system property "javax.rmi.CORBA.PortableRemoteObjectClass" to the name of the alternative class that must implement {@link PortableRemoteObjectDelegate}.

Constructor Summary
protected	PortableRemoteObject() The protected constructor calls {@link exportObject} (this).

Method Summary
static void	connect(Remote target, Remote source) Makes the remote object `a_target` ready for remote communication using the same communications runtime as for the passed `a_source` parameter.
static void	exportObject(Remote object) Makes a server object ready for remote calls.
static Object	narrow(Object object, Class narrowToInstaceOf) Narrows the passed object to conform to the given interface or IDL type.
static Remote	toStub(Remote targetImpl) Takes a server implementation object (name pattern imp) and returns a stub object that can be used to access that server object (target), name (pattern __Stub).
static void	unexportObject(Remote object) Deregister a currently exported server object from the ORB runtimes.

Constructor Detail

PortableRemoteObject

The protected constructor calls {@link exportObject} (this).

Throws: RemoteException if the exportObject(this) throws one.

Method Detail

connect

Makes the remote object a_target ready for remote communication using the same communications runtime as for the passed a_source parameter. The a_target is connected to the same ORB (and, if applicable, to the same {@link POA}) as the a_source.

Parameters: a_target the target to connect to ORB, must be an instance of either {@link ObjectImpl} (Stubs and old-style ties) or {@link Tie}. a_source the object, providing the connection information, must be an instance of either {@link ObjectImpl} (Stubs and old-style ties) or {@link Servant} (the next-generation Ties supporting {@link POA}).

Throws: RemoteException if the target is already connected to another ORB.

exportObject

Makes a server object ready for remote calls. The subclasses of PortableRemoteObject do not need to call this method, as it is called by the constructor.

This method only creates a tie object and caches it for future usage. The created tie does not have a delegate or an ORB associated.

Parameters: object the object to export.

Throws: RemoteException if export fails due any reason.

narrow

Narrows the passed object to conform to the given interface or IDL type. In RMI-IIOP, this method replaces the narrow(org.omg.CORBA.Object) method that was present in the CORBA Helpers. This method frequently returns different instance and cannot be replaced by the direct cast. The typical narrowing cases (all supported by GNU Classpath) are:

A CORBA object (for instance, returned by the {@link ORB#string_to_object} or from the naming service) can be narrowed into interface, derived from Remote. The method will try to locate an appropriate {@link Stub} by the name pattern (_*_Stub). If the object being narrowed is connected to an ORB, the returned instance will inherit that connection, representing the same remote (or local) object, but now with the possibility to invoke remote methods.
A CORBA object may be directly narrowed into the appropriate {@link Stub} class, if it is and passed as a second parameter. This allows to use non-standard stubs without parameterless constructors.
Any two classes, derived from the {@link ObjectImpl} (may be Stub's) can be narrowed one into another (a delegate is transferred).
An implementation of Remote can be narrowed into {@link Tie} that can later connected to an ORB, making the methods accessible remotely. The Remote being narrowed normally provides a local implementation, but you can also narrow remote Stub, creating "forwarding Tie".
null is narrowed into null regardless of the second parameter.
A {@link Tie} can be narrowed into Remote, representing the implementation for this Tie (if one is set).

Parameters: object the object like CORBA Object, Stub or Remote that must be narrowed to the given interface. narrowToInstaceOf the class of the interface to that the object must be narrowed.

Returns: On success, an object of type narrowTo or null, if narrowFrom = null.

Throws: ClassCastException if no narrowing is possible.

toStub

Takes a server implementation object (name pattern *imp) and returns a stub object that can be used to access that server object (target), name (pattern _*_Stub). The returned stub is not connected to any ORB and must be explicitly connected using {@link #connect}.

The method signature prevents it from returning stubs that does not implement Remote (ClassCastException will be thrown).

Parameters: target a server side object implementation.

Returns: a stub object that can be used to access that server object.

Throws: NoSuchObjectException if a stub class cannot be located by supposed name pattern, or an instance of stub fails to be instantiated. ClassCastException if the stub class can be located, but it does not inherit from Remote. BAD_PARAM if the name of the passed class does not match the implementation name pattern (does not end by 'Impl').

Class PortableRemoteObject