NDC xref

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    1   /**
    2    * Copyright (c) 2004-2011 QOS.ch
    3    * All rights reserved.
    4    *
    5    * Permission is hereby granted, free  of charge, to any person obtaining
    6    * a  copy  of this  software  and  associated  documentation files  (the
    7    * "Software"), to  deal in  the Software without  restriction, including
    8    * without limitation  the rights to  use, copy, modify,  merge, publish,
    9    * distribute,  sublicense, and/or sell  copies of  the Software,  and to
    10   * permit persons to whom the Software  is furnished to do so, subject to
    11   * the following conditions:
    12   *
    13   * The  above  copyright  notice  and  this permission  notice  shall  be
    14   * included in all copies or substantial portions of the Software.
    15   *
    16   * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
    17   * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
    18   * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
    19   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
    20   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    21   * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
    22   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    23   *
    24   */
    25  package org.slf4j;
    26
    27  import org.slf4j.MDC;
    28
    29  public class NDC {
    30    public final static String PREFIX = "NDC";
    31
    32    private static int size() {
    33      int i = 0;
    34      while (true) {
    35        String val = MDC.get(PREFIX + i);
    36        if (val != null) {
    37          i++;
    38        } else {
    39          break;
    40        }
    41      }
    42      return i;
    43    }
    44
    45    public static void push(String val) {
    46      int next = size();
    47      MDC.put(PREFIX + next, val);
    48    }
    49
    50    public static String pop() {
    51      int next = size();
    52      if(next == 0) {
    53        return "";
    54      }
    55      int last = next-1;
    56      String key = PREFIX+last;
    57      String val = MDC.get(key);
    58      MDC.remove(key);
    59      return val;
    60    }
    61
    62  }