/*

 * Copyright 1996-2004 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.rmi.server;

import java.io.*;

import java.rmi.Remote;

import java.rmi.server.RemoteStub;

import sun.rmi.transport.ObjectTable;

import sun.rmi.transport.Target;

/**

 * A MarshalOutputStream extends ObjectOutputStream to add functions

 * specific to marshaling of remote object references. If it is

 * necessary to serialize remote objects or objects that contain

 * references to remote objects a MarshalOutputStream must be used

 * instead of ObjectOutputStream. <p>

 *

 * A new MarshalOutputStream is constructed to serialize remote

 * objects or graphs containing remote objects. Objects are written to

 * the stream using the ObjectOutputStream.writeObject method. <p>

 *

 * MarshalOutputStream maps remote objects to the corresponding remote

 * stub and embeds the location from which to load the stub

 * classes. The location may be ignored by the client but is supplied.

 */

public class MarshalOutputStream extends ObjectOutputStream

{

    /**

     * Creates a marshal output stream with protocol version 1.

     */

    public MarshalOutputStream(OutputStream out) throws IOException {

        this(out, ObjectStreamConstants.PROTOCOL_VERSION_1);

    }

    /**

     * Creates a marshal output stream with the given protocol version.

     */

    public MarshalOutputStream(OutputStream out, int protocolVersion)

        throws IOException

    {

        super(out);

        this.useProtocolVersion(protocolVersion);

        java.security.AccessController.doPrivileged(

                                    new java.security.PrivilegedAction() {

            public Object run() {

                enableReplaceObject(true);

                return null;

            }

        });

    }

    /**

     * Checks for objects that are instances of java.rmi.Remote

     * that need to be serialized as proxy objects.

     */

    protected final Object replaceObject(Object obj) throws IOException {

        if ((obj instanceof Remote) && !(obj instanceof RemoteStub)) {

            Target target = ObjectTable.getTarget((Remote) obj);

            if (target != null) {

                return target.getStub();

            }

        }

        return obj;

    }

    /**

     * Serializes a location from which to load the the specified class.

     */

    protected void annotateClass(Class<?> cl) throws IOException {

        writeLocation(java.rmi.server.RMIClassLoader.getClassAnnotation(cl));

    }

    /**

     * Serializes a location from which to load the specified class.

     */

    protected void annotateProxyClass(Class<?> cl) throws IOException {

        annotateClass(cl);

    }

    /**

     * Writes the location for the class into the stream.  This method can

     * be overridden by subclasses that store this annotation somewhere

     * else than as the next object in the stream, as is done by this class.

     */

    protected void writeLocation(String location) throws IOException {

        writeObject(location);

    }

}