1 /*
2 * Copyright 1996-2004 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package sun.rmi.server;
27
28 import java.io;
29 import java.rmi.Remote;
30 import java.rmi.server.RemoteStub;
31 import sun.rmi.transport.ObjectTable;
32 import 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 */
49 public 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 protected final Object replaceObject(Object obj) throws IOException {
80 if ((obj instanceof Remote) && !(obj instanceof RemoteStub)) {
81 Target target = ObjectTable.getTarget((Remote) obj);
82 if (target != null) {
83 return target.getStub();
84 }
85 }
86 return obj;
87 }
88
89 /**
90 * Serializes a location from which to load the the specified class.
91 */
92 protected void annotateClass(Class<?> cl) throws IOException {
93 writeLocation(java.rmi.server.RMIClassLoader.getClassAnnotation(cl));
94 }
95
96 /**
97 * Serializes a location from which to load the specified class.
98 */
99 protected void annotateProxyClass(Class<?> cl) throws IOException {
100 annotateClass(cl);
101 }
102
103 /**
104 * Writes the location for the class into the stream. This method can
105 * be overridden by subclasses that store this annotation somewhere
106 * else than as the next object in the stream, as is done by this class.
107 */
108 protected void writeLocation(String location) throws IOException {
109 writeObject(location);
110 }
111 }
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