001/* PortableRemoteObjectDelegate.java -- Interface supporting PortableRemoteObject
002   Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.rmi.CORBA;
040
041import java.rmi.NoSuchObjectException;
042import java.rmi.Remote;
043import java.rmi.RemoteException;
044
045/**
046 * A delegate, implementing the functionality, provided by the
047 * {@link PortableRemoteObject}.
048 *
049 * The default delegate can be altered by setting the system property
050 * "javax.rmi.CORBA.PortableRemoteObjectClass" to the name of the alternative
051 * class that must implement {@link PortableRemoteObjectDelegate}.
052 *
053 * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
054 */
055public interface PortableRemoteObjectDelegate
056{
057  /**
058   * <p>
059   * Makes the remote object <code>target</code> ready for remote
060   * communication using the same communications runtime as for the passed
061   * <code>source</code> parameter. Connection normally happens implicitly
062   * when the object is sent or received as an argument on a remote method call.
063   * </p>
064   * <p>
065   * The target object is connected to the same ORB as source by calling the
066   * {@link Stub#connect} if it is a stub or by associating its tie with an ORB
067   * if it is an implementation object.
068   * </p>
069   *
070   * @param target the target object that may be either an RMI/IDL stub or an
071   * exported RMI/IDL implementation object
072   * @param source the source object may also be either an RMI/IDL stub or an
073   * exported RMI/IDL implementation object.
074   *
075   * @throws RemoteException if the target is already connected to another ORB.
076   */
077  void connect(Remote target, Remote source)
078    throws RemoteException;
079
080  /**
081   * Register the passed object with the ORB runtimes, making it remotely
082   * accessible. When called on jre with no objects exported, creates a
083   * non-daemon thread that prevents jre from terminating until all objects are
084   * unexported. Also, such object cannot be collected by garbage collector.
085   * This is usually impemented via {@link Util#unexportObject}
086   *
087   * @param obj the object to export.
088   *
089   * @throws RemoteException
090   */
091  void exportObject(Remote obj)
092    throws RemoteException;
093
094  /**
095   * Narrows the passed object to conform to the given interface or IDL type.
096   * This method may return different instance and cannot be replaced by the
097   * direct cast.
098   *
099   * @param narrowFrom an object to narrow.
100   * @param narrowTo a type to that the object must be narrowed.
101   *
102   * @return On success, an object of type narrowTo or null, if narrowFrom =
103   * null.
104   *
105   * @throws ClassCastException if no narrowing is possible.
106   */
107  Object narrow(Object narrowFrom, Class narrowTo)
108    throws ClassCastException;
109
110  /**
111   * Takes a server implementation object and returns a stub object that can be
112   * used to access that server object (target). If the target is connected, the
113   * returned stub is also connected to the same ORB. If the target is
114   * unconnected, the returned stub is unconnected.
115   *
116   * @param obj a server side object.
117   * @return a stub object that can be used to access that server object.
118   *
119   * @throws NoSuchObjectException if a stub cannot be located for the given
120   * target.
121   */
122  Remote toStub(Remote obj)
123    throws NoSuchObjectException;
124
125  /**
126   * Deregister a currently exported server object from the ORB runtimes. The
127   * object to becomes available for garbage collection. This is usually
128   * impemented via {@link Util#unexportObject}
129   *
130   * @param obj the object to unexport.
131   *
132   * @throws NoSuchObjectException if the passed object is not currently
133   * exported.
134   */
135  void unexportObject(Remote obj)
136    throws NoSuchObjectException;
137}