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}