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.helpers;
26
27 import org.slf4j.spi.MDCAdapter;
28
29 import java.util.*;
30
31 /**
32 * Basic MDC implementation, which can be used with logging systems that lack
33 * out-of-the-box MDC support.
34 *
35 * This code was initially inspired by logback's LogbackMDCAdapter. However,
36 * LogbackMDCAdapter has evolved and is now considerably more sophisticated.
37 *
38 * @author Ceki Gulcu
39 * @author Maarten Bosteels
40 * @author Lukasz Cwik
41 *
42 * @since 1.5.0
43 */
44 public class BasicMDCAdapter implements MDCAdapter {
45
46 private final ThreadLocalMapOfStacks threadLocalMapOfDeques = new ThreadLocalMapOfStacks();
47
48 private final InheritableThreadLocal<Map<String, String>> inheritableThreadLocalMap = new InheritableThreadLocal<Map<String, String>>() {
49 @Override
50 protected Map<String, String> childValue(Map<String, String> parentValue) {
51 if (parentValue == null) {
52 return null;
53 }
54 return new HashMap<>(parentValue);
55 }
56 };
57
58 /**
59 * Put a context value (the <code>val</code> parameter) as identified with
60 * the <code>key</code> parameter into the current thread's context map.
61 * Note that contrary to log4j, the <code>val</code> parameter can be null.
62 *
63 * <p>
64 * If the current thread does not have a context map it is created as a side
65 * effect of this call.
66 *
67 * @throws IllegalArgumentException
68 * in case the "key" parameter is null
69 */
70 public void put(String key, String val) {
71 if (key == null) {
72 throw new IllegalArgumentException("key cannot be null");
73 }
74 Map<String, String> map = inheritableThreadLocalMap.get();
75 if (map == null) {
76 map = new HashMap<>();
77 inheritableThreadLocalMap.set(map);
78 }
79 map.put(key, val);
80 }
81
82 /**
83 * Get the context identified by the <code>key</code> parameter.
84 */
85 public String get(String key) {
86 Map<String, String> map = inheritableThreadLocalMap.get();
87 if ((map != null) && (key != null)) {
88 return map.get(key);
89 } else {
90 return null;
91 }
92 }
93
94 /**
95 * Remove the the context identified by the <code>key</code> parameter.
96 */
97 public void remove(String key) {
98 Map<String, String> map = inheritableThreadLocalMap.get();
99 if (map != null) {
100 map.remove(key);
101 }
102 }
103
104 /**
105 * Clear all entries in the MDC.
106 */
107 public void clear() {
108 Map<String, String> map = inheritableThreadLocalMap.get();
109 if (map != null) {
110 map.clear();
111 inheritableThreadLocalMap.remove();
112 }
113 }
114
115 /**
116 * Returns the keys in the MDC as a {@link Set} of {@link String}s The
117 * returned value can be null.
118 *
119 * @return the keys in the MDC
120 */
121 public Set<String> getKeys() {
122 Map<String, String> map = inheritableThreadLocalMap.get();
123 if (map != null) {
124 return map.keySet();
125 } else {
126 return null;
127 }
128 }
129
130 /**
131 * Return a copy of the current thread's context map.
132 * Returned value may be null.
133 *
134 */
135 public Map<String, String> getCopyOfContextMap() {
136 Map<String, String> oldMap = inheritableThreadLocalMap.get();
137 if (oldMap != null) {
138 return new HashMap<>(oldMap);
139 } else {
140 return null;
141 }
142 }
143
144 public void setContextMap(Map<String, String> contextMap) {
145 Map<String, String> copy = null;
146 if (contextMap != null) {
147 copy = new HashMap<>(contextMap);
148 }
149 inheritableThreadLocalMap.set(copy);
150 }
151
152 @Override
153 public void pushByKey(String key, String value) {
154 threadLocalMapOfDeques.pushByKey(key, value);
155 }
156
157 @Override
158 public String popByKey(String key) {
159 return threadLocalMapOfDeques.popByKey(key);
160 }
161
162 @Override
163 public Deque<String> getCopyOfDequeByKey(String key) {
164 return threadLocalMapOfDeques.getCopyOfDequeByKey(key);
165 }
166 @Override
167 public void clearDequeByKey(String key) {
168 threadLocalMapOfDeques.clearDequeByKey(key);
169 }
170 }