libjava/java/rmi/server/RemoteObject.java

   1 /* RemoteObject.java --
   2    Copyright (c) 1996, 1997, 1998, 1999, 2004  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package java.rmi.server;
  39
  40 import java.io.IOException;
  41 import java.io.ObjectInputStream;
  42 import java.io.ObjectOutputStream;
  43 import java.io.Serializable;
  44 import java.lang.reflect.Constructor;
  45 import java.rmi.NoSuchObjectException;
  46 import java.rmi.Remote;
  47 import java.rmi.UnmarshalException;
  48 import java.util.WeakHashMap;
  49
  50 public abstract class RemoteObject
  51         implements Remote, Serializable {
  52
  53 private static final long serialVersionUID = -3215090123894869218l;
  54
  55 protected transient RemoteRef ref;
  56
  57 private static final WeakHashMap stubs = new WeakHashMap();
  58
  59 protected RemoteObject() {
  60         this(null);
  61 }
  62
  63 protected RemoteObject(RemoteRef newref) {
  64         ref = newref;
  65 }
  66
  67 public RemoteRef getRef() {
  68         return (ref);
  69 }
  70
  71 synchronized static void addStub(Remote obj, Remote stub)
  72 {
  73   stubs.put(obj, stub);
  74 }
  75
  76 synchronized static void deleteStub(Remote obj)
  77 {
  78   stubs.remove(obj);
  79 }
  80
  81   public static Remote toStub(Remote obj) throws NoSuchObjectException
  82   {
  83     Remote stub = (Remote)stubs.get(obj);
  84
  85     if (stub == null)
  86       throw new NoSuchObjectException(obj.getClass().getName());
  87
  88     return stub;
  89   }
  90
  91 public int hashCode() {
  92         if (ref == null) {
  93                 return (0);
  94         }
  95         else {
  96                 return (ref.hashCode());
  97         }
  98 }
  99
 100 public boolean equals(Object obj) {
 101         // We only compare references.
 102         return (this == obj);
 103 }
 104
 105   public String toString()
 106   {
 107     if (ref == null)
 108       return getClass ().toString ();
 109     return (ref.toString ());
 110   }
 111
 112   private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException
 113   {
 114     String cname = in.readUTF();
 115     if (!cname.equals(""))
 116       {
 117         if (cname.equals ("UnicastRef2"))
 118           {
 119             // hack for interoperating with JDK
 120             cname = "UnicastRef";
 121             in.read (); //some unknown UnicastRef2 field
 122           }
 123
 124         cname = RemoteRef.packagePrefix + '.' + cname;
 125         try
 126           {
 127             Class cls = Class.forName(cname);
 128             ref = (RemoteRef)cls.newInstance();
 129           }
 130         catch (InstantiationException e1)
 131           {
 132             throw new UnmarshalException("failed to create ref", e1);
 133           }
 134         catch (IllegalAccessException e2)
 135           {
 136             throw new UnmarshalException("failed to create ref", e2);
 137           }
 138         ref.readExternal(in);
 139       }
 140     else
 141       {
 142         ref = (RemoteRef)in.readObject();
 143       }
 144   }
 145
 146 private void writeObject(ObjectOutputStream out) throws IOException, ClassNotFoundException {
 147         if (ref == null) {
 148                 throw new UnmarshalException("no ref to serialize");
 149         }
 150         String cname = ref.getRefClass(out);
 151         if (cname != null && cname.length() > 0) {
 152                 out.writeUTF(cname);
 153                 ref.writeExternal(out);
 154         }
 155         else {
 156                 out.writeUTF("");
 157                 out.writeObject(ref);
 158         }
 159 }
 160
 161 }