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 
  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     @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 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 }