    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}