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 
size()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 
push(String val)45     public static void push(String val) {
46         int next = size();
47         MDC.put(PREFIX + next, val);
48     }
49 
pop()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 }
63