/*
    * Copyright 2001-2004 The Apache Software Foundation.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.log4j;
  
  import org.slf4j.MDC;
  
  import java.util.Stack;
  
  /**
   * A log4j's NDC implemented in terms of SLF4J MDC primitives.
   *
   * @since SLF4J 1.6.0
   */
  
  public class NDC {
  
      public final static String PREFIX = "NDC";
  
      public static void clear() {
          int depth = getDepth();
          for (int i = 0; i < depth; i++) {
              String key = PREFIX + i;
              MDC.remove(key);
          }
      }
  
      @SuppressWarnings("rawtypes")
      public static Stack cloneStack() {
          return null;
      }
  
      @SuppressWarnings("rawtypes")
      public static void inherit(Stack stack) {
      }
  
      static public String get() {
          return null;
      }
  
      public static int getDepth() {
          int i = 0;
          while (true) {
              String val = MDC.get(PREFIX + i);
              if (val != null) {
                  i++;
              } else {
                  break;
              }
          }
          return i;
      }
  
      public static String pop() {
          int next = getDepth();
          if (next == 0) {
              return "";
          }
          int last = next - 1;
          String key = PREFIX + last;
          String val = MDC.get(key);
          MDC.remove(key);
          return val;
      }
  
      public static String peek() {
          int next = getDepth();
          if (next == 0) {
              return "";
          }
          int last = next - 1;
          String key = PREFIX + last;
          String val = MDC.get(key);
          return val;
      }
  
      public static void push(String message) {
          int next = getDepth();
          MDC.put(PREFIX + next, message);
      }
  
      static public void remove() {
          clear();
      }
  
      static public void setMaxDepth(int maxDepth) {
     }
 
 }