diff --git a/library/log4php/LoggerHierarchy.php b/library/log4php/LoggerHierarchy.php
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+++ b/library/log4php/LoggerHierarchy.php
@@ -0,0 +1,257 @@
+<?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
+ */
+
+/**
+ * This class is specialized in retrieving loggers by name and also maintaining
+ * the logger hierarchy. The logger hierarchy is dealing with the several Log-Levels
+ * Logger can have. From log4j website:
+ *
+ * "A logger is said to be an ancestor of another logger if its name followed
+ * by a dot is a prefix of the descendant logger name. A logger is said to be
+ * a parent of a child logger if there are no ancestors between itself and the
+ * descendant logger."
+ *
+ * Child Loggers do inherit their Log-Levels from their Ancestors. They can
+ * increase their Log-Level compared to their Ancestors, but they cannot decrease it.
+ *
+ * <p>The casual user does not have to deal with this class directly.</p>
+ *
+ * <p>The structure of the logger hierarchy is maintained by the
+ * getLogger method. The hierarchy is such that children link
+ * to their parent but parents do not have any pointers to their
+ * children. Moreover, loggers can be instantiated in any order, in
+ * particular descendant before ancestor.</p>
+ *
+ * <p>In case a descendant is created before a particular ancestor,
+ * then it creates a provision node for the ancestor and adds itself
+ * to the provision node. Other descendants of the same ancestor add
+ * themselves to the previously created provision node.</p>
+ *
+ * @version $Revision: 1394956 $
+ * @package log4php
+ */
+class LoggerHierarchy {
+
+    /** Array holding all Logger instances. */
+    protected $loggers = array();
+
+    /**
+     * The root logger.
+     * @var RootLogger
+     */
+    protected $root;
+
+    /**
+     * The logger renderer map.
+     * @var LoggerRendererMap
+     */
+    protected $rendererMap;
+
+    /**
+     * Main level threshold. Events with lower level will not be logged by any
+     * logger, regardless of it's configuration.
+     * @var LoggerLevel
+     */
+    protected $threshold;
+
+    /**
+     * Creates a new logger hierarchy.
+     * @param LoggerRoot $root The root logger.
+     */
+    public function __construct(LoggerRoot $root) {
+        $this->root = $root;
+        $this->setThreshold(LoggerLevel::getLevelAll());
+        $this->rendererMap = new LoggerRendererMap();
+    }
+
+    /**
+     * Clears all loggers.
+     */
+    public function clear() {
+        $this->loggers = array();
+    }
+
+    /**
+     * Check if the named logger exists in the hierarchy.
+     * @param string $name
+     * @return boolean
+     */
+    public function exists($name) {
+        return isset($this->loggers[$name]);
+    }
+
+    /**
+     * Returns all the currently defined loggers in this hierarchy as an array.
+     * @return array
+     */
+    public function getCurrentLoggers() {
+        return array_values($this->loggers);
+    }
+
+    /**
+     * Returns a named logger instance logger. If it doesn't exist, one is created.
+     *
+     * @param string $name Logger name
+     * @return Logger Logger instance.
+     */
+    public function getLogger($name) {
+        if (!isset($this->loggers[$name])) {
+            $logger = new Logger($name);
+
+            $nodes = explode('.', $name);
+            $firstNode = array_shift($nodes);
+
+            // if name is not a first node but another first node is their
+            if ($firstNode != $name and isset($this->loggers[$firstNode])) {
+                $logger->setParent($this->loggers[$firstNode]);
+            } else {
+                // if there is no father, set root logger as father
+                $logger->setParent($this->root);
+            }
+
+            // if there are more nodes than one
+            if (count($nodes) > 0) {
+                // find parent node
+                foreach ($nodes as $node) {
+                    $parentNode = "$firstNode.$node";
+                    if (isset($this->loggers[$parentNode]) and $parentNode != $name) {
+                        $logger->setParent($this->loggers[$parentNode]);
+                    }
+                    $firstNode .= ".$node";
+                }
+            }
+
+            $this->loggers[$name] = $logger;
+        }
+
+        return $this->loggers[$name];
+    }
+
+    /**
+     * Returns the logger renderer map.
+     * @return LoggerRendererMap
+     */
+    public function getRendererMap() {
+        return $this->rendererMap;
+    }
+
+    /**
+     * Returns the root logger.
+     * @return LoggerRoot
+     */
+    public function getRootLogger() {
+        return $this->root;
+    }
+
+    /**
+     * Returns the main threshold level.
+     * @return LoggerLevel
+     */
+    public function getThreshold() {
+        return $this->threshold;
+    }
+
+    /**
+     * Returns true if the hierarchy is disabled for given log level and false
+     * otherwise.
+     * @return boolean
+     */
+    public function isDisabled(LoggerLevel $level) {
+        return ($this->threshold->toInt() > $level->toInt());
+    }
+
+    /**
+     * Reset all values contained in this hierarchy instance to their
+     * default.
+     *
+     * This removes all appenders from all loggers, sets
+     * the level of all non-root loggers to <i>null</i>,
+     * sets their additivity flag to <i>true</i> and sets the level
+     * of the root logger to {@link LOGGER_LEVEL_DEBUG}.
+     *
+     * <p>Existing loggers are not removed. They are just reset.
+     *
+     * <p>This method should be used sparingly and with care as it will
+     * block all logging until it is completed.</p>
+     */
+    public function resetConfiguration() {
+        $root = $this->getRootLogger();
+
+        $root->setLevel(LoggerLevel::getLevelDebug());
+        $this->setThreshold(LoggerLevel::getLevelAll());
+        $this->shutDown();
+
+        foreach ($this->loggers as $logger) {
+            $logger->setLevel(null);
+            $logger->setAdditivity(true);
+            $logger->removeAllAppenders();
+        }
+
+        $this->rendererMap->reset();
+        LoggerAppenderPool::clear();
+    }
+
+    /**
+     * Sets the main threshold level.
+     * @param LoggerLevel $l
+     */
+    public function setThreshold(LoggerLevel $threshold) {
+        $this->threshold = $threshold;
+    }
+
+    /**
+     * Shutting down a hierarchy will <i>safely</i> close and remove
+     * all appenders in all loggers including the root logger.
+     *
+     * The shutdown method is careful to close nested
+     * appenders before closing regular appenders. This is allows
+     * configurations where a regular appender is attached to a logger
+     * and again to a nested appender.
+     *
+     * @todo Check if the last paragraph is correct.
+     */
+    public function shutdown() {
+        $this->root->removeAllAppenders();
+
+        foreach ($this->loggers as $logger) {
+            $logger->removeAllAppenders();
+        }
+    }
+
+    /**
+     * Prints the current Logger hierarchy tree. Useful for debugging.
+     */
+    public function printHierarchy() {
+        $this->printHierarchyInner($this->getRootLogger(), 0);
+    }
+
+    private function printHierarchyInner(Logger $current, $level) {
+        for ($i = 0; $i < $level; $i++) {
+            echo ($i == $level - 1) ? "|--" : "|  ";
+        }
+        echo $current->getName() . "\n";
+
+        foreach ($this->loggers as $logger) {
+            if ($logger->getParent() == $current) {
+                $this->printHierarchyInner($logger, $level + 1);
+            }
+        }
+    }
+}