1/*
2 * Copyright 2001-2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package org.apache.log4j;
18
19import org.slf4j.MDC;
20
21import java.util.Stack;
22
23/**
24 * A log4j's NDC implemented in terms of SLF4J MDC primitives.
25 *
26 * @since SLF4J 1.6.0
27 */
28
29public class NDC {
30
31    public final static String PREFIX = "NDC";
32
33    public static void clear() {
34        int depth = getDepth();
35        for (int i = 0; i < depth; i++) {
36            String key = PREFIX + i;
37            MDC.remove(key);
38        }
39    }
40
41    @SuppressWarnings("rawtypes")
42    public static Stack cloneStack() {
43        return null;
44    }
45
46    @SuppressWarnings("rawtypes")
47    public static void inherit(Stack stack) {
48    }
49
50    static public String get() {
51        return null;
52    }
53
54    public static int getDepth() {
55        int i = 0;
56        while (true) {
57            String val = MDC.get(PREFIX + i);
58            if (val != null) {
59                i++;
60            } else {
61                break;
62            }
63        }
64        return i;
65    }
66
67    public static String pop() {
68        int next = getDepth();
69        if (next == 0) {
70            return "";
71        }
72        int last = next - 1;
73        String key = PREFIX + last;
74        String val = MDC.get(key);
75        MDC.remove(key);
76        return val;
77    }
78
79    public static String peek() {
80        int next = getDepth();
81        if (next == 0) {
82            return "";
83        }
84        int last = next - 1;
85        String key = PREFIX + last;
86        String val = MDC.get(key);
87        return val;
88    }
89
90    public static void push(String message) {
91        int next = getDepth();
92        MDC.put(PREFIX + next, message);
93    }
94
95    static public void remove() {
96        clear();
97    }
98
99    static public void setMaxDepth(int maxDepth) {
100    }
101
102}
103