new file mode 100644
--- /dev/null
+++ b/library/log4php/LoggerMDC.php
@@ -0,0 +1,88 @@
+<?php
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @package log4php
+ */
+
+/**
+ * The LoggerMDC class provides _mapped diagnostic contexts_.
+ *
+ * A Mapped Diagnostic Context, or MDC in short, is an instrument for
+ * distinguishing interleaved log output from different sources. Log output
+ * is typically interleaved when a server handles multiple clients
+ * near-simultaneously.
+ *
+ * This class is similar to the {@link LoggerNDC} class except that
+ * it is based on a map instead of a stack.
+ *
+ * @version $Revision: 1343630 $
+ * @since 0.3
+ * @package log4php
+ */
+class LoggerMDC {
+
+    /** Holds the context map. */
+    private static $map = array();
+
+    /**
+     * Stores a context value as identified with the key parameter into the
+     * context map.
+     *
+     * @param string $key the key
+     * @param string $value the value
+     */
+    public static function put($key, $value) {
+        self::$map[$key] = $value;
+    }
+
+    /**
+     * Returns the context value identified by the key parameter.
+     *
+     * @param string $key The key.
+     * @return string The context or an empty string if no context found
+     *    for given key.
+     */
+    public static function get($key) {
+        return isset(self::$map[$key]) ? self::$map[$key] : '';
+    }
+
+    /**
+     * Returns the contex map as an array.
+     * @return array The MDC context map.
+     */
+    public static function getMap() {
+        return self::$map;
+    }
+
+    /**
+     * Removes the the context identified by the key parameter.
+     *
+     * Only affects user mappings, not $_ENV or $_SERVER.
+     *
+     * @param string $key The key to be removed.
+     */
+    public static function remove($key) {
+        unset(self::$map[$key]);
+    }
+
+    /**
+     * Clears the mapped diagnostic context.
+     */
+    public static function clear() {
+        self::$map = array();
+    }
+}