/* RemoteRef.java --
   Copyright (c) 1996, 1997, 1998, 1999, 2004, 2006  
   Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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exception statement from your version. */


package java.rmi.server;

import java.io.Externalizable;
import java.io.ObjectOutput;
import java.lang.reflect.Method;
import java.rmi.Remote;
import java.rmi.RemoteException;

/**
 * Represents a handler to the remote object. Each instance of the
 * {@link RemoteStub} contains such handler and uses it to invoke remote
 * methods via {@link #invoke(Remote, Method, Object[], long)}.
 */
public interface RemoteRef extends Externalizable
{
  /**
   *  Indicates compatibility with JDK 1.1.*
   */
  long serialVersionUID = 3632638527362204081L;
  
  /**
   * For binary compatibility with the JDK, the string "sun.rmi.server".
   * Not actually used for anything.
   */
  String packagePrefix = "sun.rmi.server";

  /**
   * @deprecated use {@link #invoke(Remote, Method, Object[], long)} instead.
   */
  void invoke (RemoteCall call) throws Exception;
  
  /**
   * Invoke a method. This method either returns the result of remote invocation
   * or throws RemoteException if the remote call failed. Other exceptions may
   * be thrown if some problem has occured in the application level.
   * 
   * @param obj the object, containing the remote reference (for instance,
   *          remote stub, generated by rmic).
   * @param method the method to invoke
   * @param params the method parameters
   * @param methodHash a persistent hash code that can be used to represent a
   *          method
   * @return the result of the remote invocation
   * @throws RemoteException if the remote call has failed
   * @throws Exception if one is raised at the application level
   */
  Object invoke (Remote obj, Method method, Object[] params, long methodHash)
    throws Exception;
  
  /**
   * @deprecated use {@link #invoke(Remote, Method, Object[], long)} instead.
   */
  RemoteCall newCall (RemoteObject obj, Operation[] op, int opnum, long hash)
    throws RemoteException;

  /**
   * @deprecated use {@link #invoke(Remote, Method, Object[], long)} instead.
   */
  void done (RemoteCall call) throws RemoteException;
  
  /**
   * Compare two remote objects for equality. The references are equal if
   * they point to the same remote object.
   * 
   * @param ref the reference to compare.
   * 
   * @return true if this and passed references both point to the same remote
   * object, false otherwise.
   */
  boolean remoteEquals (RemoteRef ref);
  
  /**
   * Get the hashcode for a remote object. Two remote object stubs, referring
   * to the same remote object, have the same hash code.
   * 
   * @return the hashcode of the remote object
   */
  int remoteHashCode();
  
  
  /**
   * Returns the class name of the reference type that must be written to the
   * given stream. When writing, this returned name is passed first, and
   * the reference.writeExternal(out) writes the reference specific data.
   * 
   * @param out the stream, where the data must be written 
   * 
   * @return the class name. 
   */
  String getRefClass (ObjectOutput out);
  
  /**
   * Get the string representation of this remote reference.
   * 
   * @return the string representation.
   */
  String remoteToString();
}