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<Map<String, String>> inheritableThreadLocal = new InheritableThreadLocal<Map<String, String>>(); 47 isJDK14()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 * Put a context value (the <code>val</code> parameter) as identified with 62 * the <code>key</code> parameter into the current thread's context map. 63 * Note that contrary to log4j, the <code>val</code> parameter can be null. 64 * 65 * <p> 66 * If the current thread does not have a context map it is created as a side 67 * effect of this call. 68 * 69 * @throws IllegalArgumentException 70 * in case the "key" parameter is null 71 */ put(String key, String val)72 public void put(String key, String val) { 73 if (key == null) { 74 throw new IllegalArgumentException("key cannot be null"); 75 } 76 Map<String, String> map = (Map<String, String>) inheritableThreadLocal.get(); 77 if (map == null) { 78 map = Collections.<String, String> synchronizedMap(new HashMap<String, String>()); 79 inheritableThreadLocal.set(map); 80 } 81 map.put(key, val); 82 } 83 84 /** 85 * Get the context identified by the <code>key</code> parameter. 86 */ get(String key)87 public String get(String key) { 88 Map<String, String> Map = (Map<String, String>) inheritableThreadLocal.get(); 89 if ((Map != null) && (key != null)) { 90 return (String) Map.get(key); 91 } else { 92 return null; 93 } 94 } 95 96 /** 97 * Remove the the context identified by the <code>key</code> parameter. 98 */ remove(String key)99 public void remove(String key) { 100 Map<String, String> map = (Map<String, String>) inheritableThreadLocal.get(); 101 if (map != null) { 102 map.remove(key); 103 } 104 } 105 106 /** 107 * Clear all entries in the MDC. 108 */ clear()109 public void clear() { 110 Map<String, String> map = (Map<String, String>) inheritableThreadLocal.get(); 111 if (map != null) { 112 map.clear(); 113 // the InheritableThreadLocal.remove method was introduced in JDK 1.5 114 // Thus, invoking clear() on previous JDK 1.4 will fail 115 if (isJDK14()) { 116 inheritableThreadLocal.set(null); 117 } else { 118 inheritableThreadLocal.remove(); 119 } 120 } 121 } 122 123 /** 124 * Returns the keys in the MDC as a {@link Set} of {@link String}s The 125 * returned value can be null. 126 * 127 * @return the keys in the MDC 128 */ getKeys()129 public Set<String> getKeys() { 130 Map<String, String> map = (Map<String, String>) inheritableThreadLocal.get(); 131 if (map != null) { 132 return map.keySet(); 133 } else { 134 return null; 135 } 136 } 137 138 /** 139 * Return a copy of the current thread's context map. 140 * Returned value may be null. 141 * 142 */ getCopyOfContextMap()143 public Map<String, String> getCopyOfContextMap() { 144 Map<String, String> oldMap = (Map<String, String>) inheritableThreadLocal.get(); 145 if (oldMap != null) { 146 Map<String, String> newMap = Collections.<String, String> synchronizedMap(new HashMap<String, String>()); 147 synchronized (oldMap) { 148 newMap.putAll(oldMap); 149 } 150 return newMap; 151 } else { 152 return null; 153 } 154 } 155 setContextMap(Map<String, String> contextMap)156 public void setContextMap(Map<String, String> contextMap) { 157 Map<String, String> map = Collections.<String, String> synchronizedMap(new HashMap<String, String>(contextMap)); 158 inheritableThreadLocal.set(map); 159 } 160 161 } 162