001/** 002 * Copyright (c) 2004-2011 QOS.ch 003 * All rights reserved. 004 * 005 * Permission is hereby granted, free of charge, to any person obtaining 006 * a copy of this software and associated documentation files (the 007 * "Software"), to deal in the Software without restriction, including 008 * without limitation the rights to use, copy, modify, merge, publish, 009 * distribute, sublicense, and/or sell copies of the Software, and to 010 * permit persons to whom the Software is furnished to do so, subject to 011 * the following conditions: 012 * 013 * The above copyright notice and this permission notice shall be 014 * included in all copies or substantial portions of the Software. 015 * 016 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 017 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 018 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 019 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 020 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 021 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 022 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 023 * 024 */ 025package org.slf4j; 026 027import org.slf4j.MDC; 028 029public class NDC { 030 public final static String PREFIX = "NDC"; 031 032 private static int size() { 033 int i = 0; 034 while (true) { 035 String val = MDC.get(PREFIX + i); 036 if (val != null) { 037 i++; 038 } else { 039 break; 040 } 041 } 042 return i; 043 } 044 045 public static void push(String val) { 046 int next = size(); 047 MDC.put(PREFIX + next, val); 048 } 049 050 public static String pop() { 051 int next = size(); 052 if (next == 0) { 053 return ""; 054 } 055 int last = next - 1; 056 String key = PREFIX + last; 057 String val = MDC.get(key); 058 MDC.remove(key); 059 return val; 060 } 061 062}