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 import java.util.Map;
31
32 /**
33 * Basic MDC implementation, which can be used with logging systems that lack
34 * out-of-the-box MDC support.
35 *
36 * This code was initially inspired by logback's LogbackMDCAdapter. However,
37 * LogbackMDCAdapter has evolved and is now considerably more sophisticated.
38 *
39 * @author Ceki Gulcu
40 * @author Maarten Bosteels
41 *
42 * @since 1.5.0
43 */
44 public class BasicMDCAdapter implements MDCAdapter {
45
46 private InheritableThreadLocal inheritableThreadLocal = new InheritableThreadLocal();
47
48 static boolean isJDK14() {
49 try {
50 String javaVersion = System.getProperty("java.version");
51 return javaVersion.startsWith("1.4");
52 } catch(SecurityException se) {
53 // punt and assume JDK 1.5 or later
54 return false;
55 }
56 }
57
58 static boolean IS_JDK14 = isJDK14();
59
60
61 /**
62 * Put a context value (the <code>val</code> parameter) as identified with
63 * the <code>key</code> parameter into the current thread's context map.
64 * Note that contrary to log4j, the <code>val</code> parameter can be null.
65 *
66 * <p>
67 * If the current thread does not have a context map it is created as a side
68 * effect of this call.
69 *
70 * @throws IllegalArgumentException
71 * in case the "key" parameter is null
72 */
73 public void put(String key, String val) {
74 if (key == null) {
75 throw new IllegalArgumentException("key cannot be null");
76 }
77 Map map = (Map) inheritableThreadLocal.get();
78 if (map == null) {
79 map = Collections.synchronizedMap(new HashMap());
80 inheritableThreadLocal.set(map);
81 }
82 map.put(key, val);
83 }
84
85 /**
86 * Get the context identified by the <code>key</code> parameter.
87 */
88 public String get(String key) {
89 Map Map = (Map) inheritableThreadLocal.get();
90 if ((Map != null) && (key != null)) {
91 return (String) Map.get(key);
92 } else {
93 return null;
94 }
95 }
96
97 /**
98 * Remove the the context identified by the <code>key</code> parameter.
99 */
100 public void remove(String key) {
101 Map map = (Map) inheritableThreadLocal.get();
102 if (map != null) {
103 map.remove(key);
104 }
105 }
106
107 /**
108 * Clear all entries in the MDC.
109 */
110 public void clear() {
111 Map map = (Map) inheritableThreadLocal.get();
112 if (map != null) {
113 map.clear();
114 // the InheritableThreadLocal.remove method was introduced in JDK 1.5
115 // Thus, invoking clear() on previous JDK 1.4 will fail
116 if(isJDK14()) {
117 inheritableThreadLocal.set(null);
118 } else {
119 inheritableThreadLocal.remove();
120 }
121 }
122 }
123
124 /**
125 * Returns the keys in the MDC as a {@link Set} of {@link String}s The
126 * returned value can be null.
127 *
128 * @return the keys in the MDC
129 */
130 public Set getKeys() {
131 Map map = (Map) inheritableThreadLocal.get();
132 if (map != null) {
133 return map.keySet();
134 } else {
135 return null;
136 }
137 }
138 /**
139 * Return a copy of the current thread's context map.
140 * Returned value may be null.
141 *
142 */
143 public Map getCopyOfContextMap() {
144 Map oldMap = (Map) inheritableThreadLocal.get();
145 if (oldMap != null) {
146 Map newMap = Collections.synchronizedMap(new HashMap());
147 synchronized (oldMap) {
148 newMap.putAll(oldMap);
149 }
150 return newMap;
151 } else {
152 return null;
153 }
154 }
155
156 public void setContextMap(Map contextMap) {
157 Map map = Collections.synchronizedMap(new HashMap(contextMap));
158 inheritableThreadLocal.set(map);
159 }
160
161 }