001    /* RemoteRef.java --
002       Copyright (c) 1996, 1997, 1998, 1999, 2004, 2006  
003       Free Software Foundation, Inc.
004    
005    This file is part of GNU Classpath.
006    
007    GNU Classpath is free software; you can redistribute it and/or modify
008    it under the terms of the GNU General Public License as published by
009    the Free Software Foundation; either version 2, or (at your option)
010    any later version.
011     
012    GNU Classpath is distributed in the hope that it will be useful, but
013    WITHOUT ANY WARRANTY; without even the implied warranty of
014    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
015    General Public License for more details.
016    
017    You should have received a copy of the GNU General Public License
018    along with GNU Classpath; see the file COPYING.  If not, write to the
019    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
020    02110-1301 USA.
021    
022    Linking this library statically or dynamically with other modules is
023    making a combined work based on this library.  Thus, the terms and
024    conditions of the GNU General Public License cover the whole
025    combination.
026    
027    As a special exception, the copyright holders of this library give you
028    permission to link this library with independent modules to produce an
029    executable, regardless of the license terms of these independent
030    modules, and to copy and distribute the resulting executable under
031    terms of your choice, provided that you also meet, for each linked
032    independent module, the terms and conditions of the license of that
033    module.  An independent module is a module which is not derived from
034    or based on this library.  If you modify this library, you may extend
035    this exception to your version of the library, but you are not
036    obligated to do so.  If you do not wish to do so, delete this
037    exception statement from your version. */
038    
039    
040    package java.rmi.server;
041    
042    import java.io.Externalizable;
043    import java.io.ObjectOutput;
044    import java.lang.reflect.Method;
045    import java.rmi.Remote;
046    import java.rmi.RemoteException;
047    
048    /**
049     * Represents a handler to the remote object. Each instance of the
050     * {@link RemoteStub} contains such handler and uses it to invoke remote
051     * methods via {@link #invoke(Remote, Method, Object[], long)}.
052     */
053    public interface RemoteRef extends Externalizable
054    {
055      /**
056       *  Indicates compatibility with JDK 1.1.*
057       */
058      long serialVersionUID = 3632638527362204081L;
059      
060      /**
061       * For binary compatibility with the JDK, the string "sun.rmi.server".
062       * Not actually used for anything.
063       */
064      String packagePrefix = "sun.rmi.server";
065    
066      /**
067       * @deprecated use {@link #invoke(Remote, Method, Object[], long)} instead.
068       */
069      void invoke (RemoteCall call) throws Exception;
070      
071      /**
072       * Invoke a method. This method either returns the result of remote invocation
073       * or throws RemoteException if the remote call failed. Other exceptions may
074       * be thrown if some problem has occured in the application level.
075       * 
076       * @param obj the object, containing the remote reference (for instance,
077       *          remote stub, generated by rmic).
078       * @param method the method to invoke
079       * @param params the method parameters
080       * @param methodHash a persistent hash code that can be used to represent a
081       *          method
082       * @return the result of the remote invocation
083       * @throws RemoteException if the remote call has failed
084       * @throws Exception if one is raised at the application level
085       */
086      Object invoke (Remote obj, Method method, Object[] params, long methodHash)
087        throws Exception;
088      
089      /**
090       * @deprecated use {@link #invoke(Remote, Method, Object[], long)} instead.
091       */
092      RemoteCall newCall (RemoteObject obj, Operation[] op, int opnum, long hash)
093        throws RemoteException;
094    
095      /**
096       * @deprecated use {@link #invoke(Remote, Method, Object[], long)} instead.
097       */
098      void done (RemoteCall call) throws RemoteException;
099      
100      /**
101       * Compare two remote objects for equality. The references are equal if
102       * they point to the same remote object.
103       * 
104       * @param ref the reference to compare.
105       * 
106       * @return true if this and passed references both point to the same remote
107       * object, false otherwise.
108       */
109      boolean remoteEquals (RemoteRef ref);
110      
111      /**
112       * Get the hashcode for a remote object. Two remote object stubs, referring
113       * to the same remote object, have the same hash code.
114       * 
115       * @return the hashcode of the remote object
116       */
117      int remoteHashCode();
118      
119      
120      /**
121       * Returns the class name of the reference type that must be written to the
122       * given stream. When writing, this returned name is passed first, and
123       * the reference.writeExternal(out) writes the reference specific data.
124       * 
125       * @param out the stream, where the data must be written 
126       * 
127       * @return the class name. 
128       */
129      String getRefClass (ObjectOutput out);
130      
131      /**
132       * Get the string representation of this remote reference.
133       * 
134       * @return the string representation.
135       */
136      String remoteToString();
137    }