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 }