Source for java.rmi.server.RemoteObject

   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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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.rmi.NoSuchObjectException;
  45: import java.rmi.Remote;
  46: import java.rmi.UnmarshalException;
  47: import java.util.WeakHashMap;
  48: 
  49: public abstract class RemoteObject
  50:     implements Remote, Serializable {
  51: 
  52: private static final long serialVersionUID = -3215090123894869218l;
  53: 
  54: protected transient RemoteRef ref;
  55: 
  56: private static final WeakHashMap stubs = new WeakHashMap();
  57: 
  58: protected RemoteObject() {
  59:     this(null);
  60: }
  61: 
  62: protected RemoteObject(RemoteRef newref) {
  63:     ref = newref;
  64: }
  65: 
  66: public RemoteRef getRef() {
  67:     return (ref);
  68: }
  69: 
  70: synchronized static void addStub(Remote obj, Remote stub)
  71: {
  72:   stubs.put(obj, stub);
  73: }
  74: 
  75: synchronized static void deleteStub(Remote obj)
  76: {
  77:   stubs.remove(obj);
  78: }
  79: 
  80:   public static Remote toStub(Remote obj) throws NoSuchObjectException 
  81:   {
  82:     Remote stub = (Remote)stubs.get(obj);
  83: 
  84:     if (stub == null)
  85:       throw new NoSuchObjectException(obj.getClass().getName());
  86: 
  87:     return stub;
  88:   }
  89: 
  90: public int hashCode() {
  91:     if (ref == null) {
  92:         return (0);
  93:     }
  94:     else {
  95:         return (ref.hashCode());
  96:     }
  97: }
  98: 
  99: public boolean equals(Object obj) {
 100:     // We only compare references.
 101:     return (this == obj);
 102: }
 103: 
 104:   public String toString() 
 105:   {
 106:     if (ref == null)
 107:       return getClass ().toString ();
 108:     return (ref.toString ());
 109:   }
 110:   
 111:   private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException 
 112:   {
 113:     String cname = in.readUTF();
 114:     if (!cname.equals("")) 
 115:       {
 116:     if (cname.equals ("UnicastRef2"))
 117:       { 
 118:         // hack for interoperating with JDK
 119:         cname = "UnicastRef";
 120:         in.read (); //some unknown UnicastRef2 field
 121:       }
 122: 
 123:   // It would be nice to use RemoteRef.packagePrefix here, but for binary
 124:   // compatibility with the JDK that has to contain "sun.rmi.server"...
 125:     cname = "gnu.java.rmi.server." + cname;
 126:     try 
 127:       {
 128:         Class cls = Class.forName(cname);
 129:         ref = (RemoteRef)cls.newInstance();
 130:       }
 131:     catch (InstantiationException e1) 
 132:       {
 133:         throw new UnmarshalException("failed to create ref", e1);
 134:       }
 135:     catch (IllegalAccessException e2) 
 136:       {
 137:         throw new UnmarshalException("failed to create ref", e2);
 138:       }
 139:     ref.readExternal(in);
 140:       }
 141:     else 
 142:       {
 143:     ref = (RemoteRef)in.readObject();
 144:       }
 145:   }
 146: 
 147: private void writeObject(ObjectOutputStream out) throws IOException, ClassNotFoundException {
 148:     if (ref == null) {
 149:         throw new UnmarshalException("no ref to serialize");
 150:     }
 151:     String cname = ref.getRefClass(out);
 152:     if (cname != null && cname.length() > 0) {
 153:         out.writeUTF(cname);
 154:         ref.writeExternal(out);
 155:     }
 156:     else {
 157:         out.writeUTF("");
 158:         out.writeObject(ref);
 159:     }
 160: }
 161: 
 162: }