1 /*
   2  * Copyright (c) 2014 - 2016 Dynatrace and/or its affiliates. All rights reserved.
   3  * 
   4  * This file is part of the Lock Contention Tracing Subsystem for the HotSpot
   5  * Virtual Machine, which is developed at Christian Doppler Laboratory on
   6  * Monitoring and Evolution of Very-Large-Scale Software Systems. Please
   7  * contact us at <http://mevss.jku.at/> if you need additional information
   8  * or have any questions.
   9  *
  10  * This code is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 only, as
  12  * published by the Free Software Foundation.
  13  *
  14  * This code is distributed in the hope that it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17  * version 2 for more details (a copy is included in the LICENSE file that
  18  * accompanied this code).
  19  *
  20  * You should have received a copy of the GNU General Public License version
  21  * 2 along with this work. If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  */
  24 package sun.evtracing.processing.statistics.metadata;
  25 
  26 public class JavaImmutableSingleObjectStack extends JavaObjectStack {
  27 
  28         private final JavaObject object;
  29         private JavaClassStack cachedClassStack = null;
  30 
  31         public JavaImmutableSingleObjectStack(JavaObject object) {
  32                 assert (object != null);
  33                 this.object = object;
  34         }
  35 
  36         @Override
  37         public JavaObject top() {
  38                 return object;
  39         }
  40 
  41         @Override
  42         public JavaObject[] objects() {
  43                 return new JavaObject[]{ object };
  44         }
  45 
  46         @Override
  47         public void setObject(int number, JavaObject obj) {
  48                 throw new UnsupportedOperationException("immutable");
  49         }
  50 
  51         @Override
  52         public JavaClassStack getClassStack() {
  53                 if (cachedClassStack == null) {
  54                         cachedClassStack = new JavaClassStack(object.clazz());
  55                 }
  56                 return cachedClassStack;
  57         }
  58 }