/**
 * Copyright (c) 2004-2011 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 java.util.HashMap;
import java.util.Map;

import org.slf4j.IMarkerFactory;
import org.slf4j.Marker;

/**
 * An almost trivial implementation of the {@link IMarkerFactory}
 * interface which creates {@link BasicMarker} instances.
 * 
 * <p>Simple logging systems can conform to the SLF4J API by binding
 * {@link org.slf4j.MarkerFactory} with an instance of this class.
 *
 * @author Ceki G&uuml;lc&uuml;
 */
public class BasicMarkerFactory implements IMarkerFactory {

  Map markerMap = new HashMap();
  
  /**
   * Regular users should <em>not</em> create
   * <code>BasicMarkerFactory</code> instances. <code>Marker</code>
   * instances can be obtained using the static {@link
   * org.slf4j.MarkerFactory#getMarker} method.
   */
  public BasicMarkerFactory() {
  }

  /**
   * Manufacture a {@link BasicMarker} instance by name. If the instance has been 
   * created earlier, return the previously created instance. 
   * 
   * @param name the name of the marker to be created
   * @return a Marker instance
   */
  public synchronized Marker getMarker(String name) {
    if (name == null) {
      throw new IllegalArgumentException("Marker name cannot be null");
    }

    Marker marker = (Marker) markerMap.get(name);
    if (marker == null) {
      marker = new BasicMarker(name);
      markerMap.put(name, marker);
    }
    return marker;
  }
  
  /**
   * Does the name marked already exist?
   */
  public synchronized boolean exists(String name) {
    if (name == null) {
      return false;
    }
    return markerMap.containsKey(name);
  }

  public boolean detachMarker(String name) {
    if(name == null) {
      return false;
    }
    return (markerMap.remove(name) != null);
  }

  
  public Marker getDetachedMarker(String name) {
    return  new BasicMarker(name);
  }
  
  
  
}

@@ -1241,16 +1241,37 @@
 va.util.
+concurrent.Concurrent
 HashMap;
@@ -1288,16 +1288,37 @@
 va.util.
+concurrent.Concurrent
 Map;%0A%0Aim
@@ -1748,35 +1748,101 @@
 %0A%0A  
-Map markerMap = new HashMap
+private final ConcurrentMap%3CString, Marker%3E markerMap = new ConcurrentHashMap%3CString, Marker%3E
 ();%0A
@@ -2368,29 +2368,16 @@
  public 
-synchronized 
 Marker g
@@ -2526,17 +2526,8 @@
 er =
- (Marker)
  mar
@@ -2609,24 +2609,43 @@
 name);%0A     
+ Marker oldMarker =
  markerMap.p
@@ -2646,16 +2646,24 @@
 rMap.put
+IfAbsent
 (name, m
@@ -2670,16 +2670,83 @@
 arker);%0A
+      if (oldMarker != null) %7B%0A        marker = oldMarker;%0A      %7D%0A
     %7D%0A  
@@ -2818,24 +2818,24 @@
 xist?%0A   */%0A
+
   public syn
@@ -2835,21 +2835,8 @@
 lic 
-synchronized 
 bool

Fix BasicMarkerFactory by using ConcurrentMap