public class MDC extends Object
 If the underlying logging system offers MDC functionality, then SLF4J's MDC,
 i.e. this class, will delegate to the underlying system's MDC. Note that at
 this time, only two logging systems, namely log4j and logback, offer MDC
 functionality. For java.util.logging which does not support MDC,
 BasicMDCAdapter will be used. For other systems, i.e. slf4j-simple
 and slf4j-nop, NOPMDCAdapter will be used.
 
Thus, as a SLF4J user, you can take advantage of MDC in the presence of log4j, logback, or java.util.logging, but without forcing these systems as dependencies upon your users.
For more information on MDC please see the chapter on MDC in the logback manual.
Please note that all methods in this class are static.
| Modifier and Type | Class and Description | 
|---|---|
| static class  | MDC.MDCCloseableAn adapter to remove the key when done. | 
| Modifier and Type | Method and Description | 
|---|---|
| static void | clear()Clear all entries in the MDC of the underlying implementation. | 
| static String | get(String key)Get the diagnostic context identified by the  keyparameter. | 
| static Map<String,String> | getCopyOfContextMap()Return a copy of the current thread's context map, with keys and values of
 type String. | 
| static MDCAdapter | getMDCAdapter()Returns the MDCAdapter instance currently in use. | 
| static void | put(String key,
   String val)Put a diagnostic context value (the  valparameter) as identified with thekeyparameter into the current thread's diagnostic context map. | 
| static MDC.MDCCloseable | putCloseable(String key,
            String val)Put a diagnostic context value (the  valparameter) as identified with thekeyparameter into the current thread's diagnostic context map. | 
| static void | remove(String key)Remove the diagnostic context identified by the  keyparameter using
 the underlying system's MDC implementation. | 
| static void | setContextMap(Map<String,String> contextMap)Set the current thread's context map by first clearing any existing map and
 then copying the map passed as parameter. | 
public static void put(String key, String val) throws IllegalArgumentException
val parameter) as identified with the
 key parameter into the current thread's diagnostic context map. The
 key parameter cannot be null. The val parameter
 can be null only if the underlying implementation supports it.
 
 This method delegates all work to the MDC of the underlying logging system.
key - non-null keyval - value to put in the mapIllegalArgumentException - in case the "key" parameter is nullpublic static MDC.MDCCloseable putCloseable(String key, String val) throws IllegalArgumentException
val parameter) as identified with the
 key parameter into the current thread's diagnostic context map. The
 key parameter cannot be null. The val parameter
 can be null only if the underlying implementation supports it.
 This method delegates all work to the MDC of the underlying logging system.
 This method return a Closeable object who can remove key when
 close is called.
 
 Useful with Java 7 for example :
 
   try(MDC.MDCCloseable closeable = MDC.putCloseable(key, value)) {
     ....
   }
 
key - non-null keyval - value to put in the mapCloseable who can remove key when close
 is called.IllegalArgumentException - in case the "key" parameter is nullpublic static String get(String key) throws IllegalArgumentException
key parameter. The
 key parameter cannot be null.
 
 This method delegates all work to the MDC of the underlying logging system.
key - key parameter.IllegalArgumentException - in case the "key" parameter is nullpublic static void remove(String key) throws IllegalArgumentException
key parameter using
 the underlying system's MDC implementation. The key parameter
 cannot be null. This method does nothing if there is no previous value
 associated with key.key - IllegalArgumentException - in case the "key" parameter is nullpublic static void clear()
public static Map<String,String> getCopyOfContextMap()
public static void setContextMap(Map<String,String> contextMap)
contextMap - must contain only keys and values of type Stringpublic static MDCAdapter getMDCAdapter()
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