public class MDC
extends java.lang.Object

This class hides and serves as a substitute for the underlying logging system's MDC implementation. 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.

Return a copy of the current thread's context map, with keys and values of type String.

Returns the MDCAdapter instance currently in use.

Put a diagnostic context value (the val parameter) as identified with the key parameter into the current thread's diagnostic context map.

Put a diagnostic context value (the val parameter) as identified with the key parameter into the current thread's diagnostic context map.

Remove the diagnostic context identified by the key parameter using the underlying system's MDC implementation.

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(java.lang.String key,
                       java.lang.String val)
                throws java.lang.IllegalArgumentException

Put a diagnostic context value (the 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.

public static MDC.MDCCloseable putCloseable(java.lang.String key,
                                            java.lang.String val)
                                     throws java.lang.IllegalArgumentException

Put a diagnostic context value (the 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)) {

Parameters:

key - non-null key

val - value to put in the map

Returns:

a Closeable who can remove key when close is called.

Throws:

java.lang.IllegalArgumentException - in case the "key" parameter is null

public static java.lang.String get(java.lang.String key)
                            throws java.lang.IllegalArgumentException

Parameters:

key -

Returns:

the string value identified by the key parameter.

Throws:

java.lang.IllegalArgumentException - in case the "key" parameter is null

remove

public static void remove(java.lang.String key)
                   throws java.lang.IllegalArgumentException

Parameters:

key -

Throws:

java.lang.IllegalArgumentException - in case the "key" parameter is null

getCopyOfContextMap

public static java.util.Map<java.lang.String,java.lang.String> getCopyOfContextMap()

Returns:

A copy of the current thread's context map. May be null.

Since:

1.5.1

setContextMap

public static void setContextMap(java.util.Map<java.lang.String,java.lang.String> contextMap)

Parameters:

contextMap - must contain only keys and values of type String

Since:

1.5.1

getMDCAdapter

public static MDCAdapter getMDCAdapter()

Returns:

the MDcAdapter instance currently in use.

Since:

1.4.2