001    /* PortableRemoteObjectDelegate.java -- Interface supporting PortableRemoteObject
002       Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.rmi.CORBA;
040    
041    import java.rmi.NoSuchObjectException;
042    import java.rmi.Remote;
043    import 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     */
055    public 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    }