org.slf4j.helpers.BasicMDCAdapter Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of pax-logging-api Show documentation
The Pax Logging API Library is to allow for the Pax Logging Service to be reloaded without stopping the many dependent bundles. It also contains the OSGi Log Service API and the Knopflerfish Log API.
There is a newer version: 2.2.7
Show newest version
/* 
 * Copyright (c) 2004-2008 QOS.ch
 * All rights reserved.
 * 
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 * 
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 * 
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package org.slf4j.helpers;

import org.slf4j.spi.MDCAdapter;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * Basic MDC implementation, which can be used with logging systems that lack
 * out-of-the-box MDC support.
 * 
 * This code is largely based on logback's 
 * LogbackMDCAdapter.
 * 
 * @author Ceki Gulcu
 * @author Maarten Bosteels
 * 
 * @since 1.5.0
 */
public class BasicMDCAdapter implements MDCAdapter {

  private InheritableThreadLocal inheritableThreadLocal = new InheritableThreadLocal();

  /**
   * Put a context value (the val parameter) as identified with
   * the key parameter into the current thread's context map.
   * Note that contrary to log4j, the val parameter can be null.
   * 
   * 
   * If the current thread does not have a context map it is created as a side
   * effect of this call.
   * 
   * @throws IllegalArgumentException
   *                 in case the "key" parameter is null
   */
  public void put(String key, String val) {
    if (key == null) {
      throw new IllegalArgumentException("key cannot be null");
    }
    HashMap map = (HashMap) inheritableThreadLocal.get();
    if (map == null) {
      map = new HashMap();
      inheritableThreadLocal.set(map);
    }
    map.put(key, val);
  }

  /**
   * Get the context identified by the key parameter.
   */
  public String get(String key) {
    HashMap hashMap = (HashMap) inheritableThreadLocal.get();
    if ((hashMap != null) && (key != null)) {
      return (String) hashMap.get(key);
    } else {
      return null;
    }
  }

  /**
   * Remove the the context identified by the key parameter.
   */
  public void remove(String key) {
    HashMap map = (HashMap) inheritableThreadLocal.get();
    if (map != null) {
      map.remove(key);
    }
  }

  /**
   * Clear all entries in the MDC.
   */
  public void clear() {
    HashMap hashMap = (HashMap) inheritableThreadLocal.get();
    if (hashMap != null) {
      hashMap.clear();
      // the InheritableThreadLocal.remove method was introduced in JDK 1.5
      // Thus, invoking clear() on previous JDK's will fail
      inheritableThreadLocal.remove();
    }
  }

  /**
   * Returns the keys in the MDC as a {@link Set} of {@link String}s The
   * returned value can be null.
   * 
   * @return the keys in the MDC
   */
  public Set getKeys() {
    HashMap hashMap = (HashMap) inheritableThreadLocal.get();
    if (hashMap != null) {
      return hashMap.keySet();
    } else {
      return null;
    }
  }
  /**
   * Return a copy of the current thread's context map. 
   * Returned value may be null.
   * 
   */
  public Map getCopyOfContextMap() {
    HashMap hashMap = (HashMap) inheritableThreadLocal.get();
    if (hashMap != null) {
      return new HashMap(hashMap);
    } else {
      return null;
    }
  }

  public void setContextMap(Map contextMap) {
    HashMap hashMap = (HashMap) inheritableThreadLocal.get();
    if (hashMap != null) {
      hashMap.clear();
      hashMap.putAll(contextMap);
    } else {
      hashMap = new HashMap(contextMap);
      inheritableThreadLocal.set(hashMap);
    }
  }

}