1 /*
   2  * Copyright (c) 1999, 2000, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // ciNullObject
  26 //
  27 // This class represents a null reference in the VM.
  28 class ciNullObject : public ciObject {
  29   CI_PACKAGE_ACCESS
  30 
  31 private:
  32   ciNullObject() : ciObject() {}
  33 
  34   const char* type_string() { return "ciNullObject"; }
  35 
  36   void print_impl(outputStream* st);
  37 
  38 public:
  39   // Is this ciObject a Java Language Object?  That is,
  40   // is the ciObject an instance or an array
  41   bool is_java_object() { return true; }
  42 
  43   // What kind of ciObject is this?
  44   bool is_null_object() const { return true; }
  45   bool is_classless() const   { return true; }
  46 
  47   // Get the distinguished instance of this klass.
  48   static ciNullObject* make();
  49 };