1/*
2 * Copyright (c) 1996, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.rmi.server;
27
28import java.io.*;
29import java.rmi.Remote;
30import java.rmi.server.RemoteStub;
31import sun.rmi.transport.ObjectTable;
32import sun.rmi.transport.Target;
33
34/**
35 * A MarshalOutputStream extends ObjectOutputStream to add functions
36 * specific to marshaling of remote object references. If it is
37 * necessary to serialize remote objects or objects that contain
38 * references to remote objects a MarshalOutputStream must be used
39 * instead of ObjectOutputStream. <p>
40 *
41 * A new MarshalOutputStream is constructed to serialize remote
42 * objects or graphs containing remote objects. Objects are written to
43 * the stream using the ObjectOutputStream.writeObject method. <p>
44 *
45 * MarshalOutputStream maps remote objects to the corresponding remote
46 * stub and embeds the location from which to load the stub
47 * classes. The location may be ignored by the client but is supplied.
48 */
49public class MarshalOutputStream extends ObjectOutputStream
50{
51    /**
52     * Creates a marshal output stream with protocol version 1.
53     */
54    public MarshalOutputStream(OutputStream out) throws IOException {
55        this(out, ObjectStreamConstants.PROTOCOL_VERSION_1);
56    }
57
58    /**
59     * Creates a marshal output stream with the given protocol version.
60     */
61    public MarshalOutputStream(OutputStream out, int protocolVersion)
62        throws IOException
63    {
64        super(out);
65        this.useProtocolVersion(protocolVersion);
66        java.security.AccessController.doPrivileged(
67            new java.security.PrivilegedAction<Void>() {
68                public Void run() {
69                enableReplaceObject(true);
70                return null;
71            }
72        });
73    }
74
75    /**
76     * Checks for objects that are instances of java.rmi.Remote
77     * that need to be serialized as proxy objects.
78     */
79    @SuppressWarnings("deprecation")
80    protected final Object replaceObject(Object obj) throws IOException {
81        if ((obj instanceof Remote) && !(obj instanceof RemoteStub)) {
82            Target target = ObjectTable.getTarget((Remote) obj);
83            if (target != null) {
84                return target.getStub();
85            }
86        }
87        return obj;
88    }
89
90    /**
91     * Serializes a location from which to load the specified class.
92     */
93    protected void annotateClass(Class<?> cl) throws IOException {
94        writeLocation(java.rmi.server.RMIClassLoader.getClassAnnotation(cl));
95    }
96
97    /**
98     * Serializes a location from which to load the specified class.
99     */
100    protected void annotateProxyClass(Class<?> cl) throws IOException {
101        annotateClass(cl);
102    }
103
104    /**
105     * Writes the location for the class into the stream.  This method can
106     * be overridden by subclasses that store this annotation somewhere
107     * else than as the next object in the stream, as is done by this class.
108     */
109    protected void writeLocation(String location) throws IOException {
110        writeObject(location);
111    }
112}
113