1 /* 2 * Copyright 2001-2004 The Apache Software Foundation. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.apache.log4j; 18 19 import org.slf4j.MDC; 20 21 import java.util.Stack; 22 23 /** 24 * A log4j's NDC implemented in terms of SLF4J MDC primitives. 25 * 26 * @since SLF4J 1.6.0 27 */ 28 29 public class NDC { 30 31 public final static String PREFIX = "NDC"; 32 clear()33 public static void clear() { 34 int depth = getDepth(); 35 for (int i = 0; i < depth; i++) { 36 String key = PREFIX + i; 37 MDC.remove(key); 38 } 39 } 40 41 @SuppressWarnings("rawtypes") cloneStack()42 public static Stack cloneStack() { 43 return null; 44 } 45 46 @SuppressWarnings("rawtypes") inherit(Stack stack)47 public static void inherit(Stack stack) { 48 } 49 get()50 static public String get() { 51 return null; 52 } 53 getDepth()54 public static int getDepth() { 55 int i = 0; 56 while (true) { 57 String val = MDC.get(PREFIX + i); 58 if (val != null) { 59 i++; 60 } else { 61 break; 62 } 63 } 64 return i; 65 } 66 pop()67 public static String pop() { 68 int next = getDepth(); 69 if (next == 0) { 70 return ""; 71 } 72 int last = next - 1; 73 String key = PREFIX + last; 74 String val = MDC.get(key); 75 MDC.remove(key); 76 return val; 77 } 78 peek()79 public static String peek() { 80 int next = getDepth(); 81 if (next == 0) { 82 return ""; 83 } 84 int last = next - 1; 85 String key = PREFIX + last; 86 String val = MDC.get(key); 87 return val; 88 } 89 push(String message)90 public static void push(String message) { 91 int next = getDepth(); 92 MDC.put(PREFIX + next, message); 93 } 94 remove()95 static public void remove() { 96 clear(); 97 } 98 setMaxDepth(int maxDepth)99 static public void setMaxDepth(int maxDepth) { 100 } 101 102 } 103