Java example source code file (RemoteRef.java)

This example Java source code file (RemoteRef.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

deprecated, exception, object, operation, remotecall, remoteexception, remoteref, rmi, string

The RemoteRef.java Java example source code

/*
 * Copyright (c) 1996, 2004, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.rmi.server;

import java.rmi.*;

/**
 * <code>RemoteRef represents the handle for a remote object. A
 * <code>RemoteStub uses a remote reference to carry out a
 * remote method invocation to a remote object.
 *
 * @author  Ann Wollrath
 * @since   JDK1.1
 * @see     java.rmi.server.RemoteStub
 */
public interface RemoteRef extends java.io.Externalizable {

    /** indicate compatibility with JDK 1.1.x version of class. */
    static final long serialVersionUID = 3632638527362204081L;

    /**
     * Initialize the server package prefix: assumes that the
     * implementation of server ref classes (e.g., UnicastRef,
     * UnicastServerRef) are located in the package defined by the
     * prefix.
     */
    final static String packagePrefix = "sun.rmi.server";

    /**
     * Invoke a method. This form of delegating method invocation
     * to the reference allows the reference to take care of
     * setting up the connection to the remote host, marshaling
     * some representation for the method and parameters, then
     * communicating the method invocation to the remote host.
     * This method either returns the result of a method invocation
     * on the remote object which resides on the remote host or
     * throws a RemoteException if the call failed or an
     * application-level exception if the remote invocation throws
     * an exception.
     *
     * @param obj the object that contains the RemoteRef (e.g., the
     *            RemoteStub for the object.
     * @param method the method to be invoked
     * @param params the parameter list
     * @param opnum  a hash that may be used to represent the method
     * @return result of remote method invocation
     * @exception Exception if any exception occurs during remote method
     * invocation
     * @since 1.2
     */
    Object invoke(Remote obj,
                  java.lang.reflect.Method method,
                  Object[] params,
                  long opnum)
        throws Exception;

    /**
     * Creates an appropriate call object for a new remote method
     * invocation on this object.  Passing operation array and index,
     * allows the stubs generator to assign the operation indexes and
     * interpret them. The remote reference may need the operation to
     * encode in the call.
     *
     * @since JDK1.1
     * @deprecated 1.2 style stubs no longer use this method. Instead of
     * using a sequence of method calls on the stub's the remote reference
     * (<code>newCall, invoke, and done), a
     * stub uses a single method, <code>invoke(Remote, Method, Object[],
     * int)</code>, on the remote reference to carry out parameter
     * marshalling, remote method executing and unmarshalling of the return
     * value.
     *
     * @param obj remote stub through which to make call
     * @param op array of stub operations
     * @param opnum operation number
     * @param hash stub/skeleton interface hash
     * @return call object representing remote call
     * @throws RemoteException if failed to initiate new remote call
     * @see #invoke(Remote,java.lang.reflect.Method,Object[],long)
     */
    @Deprecated
    RemoteCall newCall(RemoteObject obj, Operation[] op, int opnum, long hash)
        throws RemoteException;

    /**
     * Executes the remote call.
     *
     * Invoke will raise any "user" exceptions which
     * should pass through and not be caught by the stub.  If any
     * exception is raised during the remote invocation, invoke should
     * take care of cleaning up the connection before raising the
     * "user" or remote exception.
     *
     * @since JDK1.1
     * @deprecated 1.2 style stubs no longer use this method. Instead of
     * using a sequence of method calls to the remote reference
     * (<code>newCall, invoke, and done), a
     * stub uses a single method, <code>invoke(Remote, Method, Object[],
     * int)</code>, on the remote reference to carry out parameter
     * marshalling, remote method executing and unmarshalling of the return
     * value.
     *
     * @param call object representing remote call
     * @throws Exception if any exception occurs during remote method
     * @see #invoke(Remote,java.lang.reflect.Method,Object[],long)
     */
    @Deprecated
    void invoke(RemoteCall call) throws Exception;

    /**
     * Allows the remote reference to clean up (or reuse) the connection.
     * Done should only be called if the invoke returns successfully
     * (non-exceptionally) to the stub.
     *
     * @since JDK1.1
     * @deprecated 1.2 style stubs no longer use this method. Instead of
     * using a sequence of method calls to the remote reference
     * (<code>newCall, invoke, and done), a
     * stub uses a single method, <code>invoke(Remote, Method, Object[],
     * int)</code>, on the remote reference to carry out parameter
     * marshalling, remote method executing and unmarshalling of the return
     * value.
     *
     * @param call object representing remote call
     * @throws RemoteException if remote error occurs during call cleanup
     * @see #invoke(Remote,java.lang.reflect.Method,Object[],long)
     */
    @Deprecated
    void done(RemoteCall call) throws RemoteException;

    /**
     * Returns the class name of the ref type to be serialized onto
     * the stream 'out'.
     * @param out the output stream to which the reference will be serialized
     * @return the class name (without package qualification) of the reference
     * type
     * @since JDK1.1
     */
    String getRefClass(java.io.ObjectOutput out);

    /**
     * Returns a hashcode for a remote object.  Two remote object stubs
     * that refer to the same remote object will have the same hash code
     * (in order to support remote objects as keys in hash tables).
     *
     * @return remote object hashcode
     * @see             java.util.Hashtable
     * @since JDK1.1
     */
    int remoteHashCode();

    /**
     * Compares two remote objects for equality.
     * Returns a boolean that indicates whether this remote object is
     * equivalent to the specified Object. This method is used when a
     * remote object is stored in a hashtable.
     * @param   obj     the Object to compare with
     * @return  true if these Objects are equal; false otherwise.
     * @see             java.util.Hashtable
     * @since JDK1.1
     */
    boolean remoteEquals(RemoteRef obj);

    /**
     * Returns a String that represents the reference of this remote
     * object.
     * @return string representing remote object reference
     * @since JDK1.1
     */
    String remoteToString();

}