src/Hierarchy.php

<?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.
 */

namespace Apache\Log4php;

use Apache\Log4php\Renderers\RendererMap;

/**
 * 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.
 *
 * The casual user does not have to deal with this class directly.
 *
 * 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.
 *
 * 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.
 *
 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
 * @link http://logging.apache.org/log4php
 */
class Hierarchy
{
    /** Array holding all Logger instances. */
    protected $loggers = array();

    /**
     * The root logger.
     * @var RootLogger
     */
    protected $root;

    /**
     * The logger renderer map.
     * @var RendererMap
     */
    protected $rendererMap;

    /**
     * Main level threshold. Events with lower level will not be logged by any
     * logger, regardless of it's configuration.
     * @var Level
     */
    protected $threshold;

    /**
     * Creates a new logger hierarchy.
     * @param RootLogger $root The root logger.
     */
    public function __construct(RootLogger $root)
    {
        $this->root = $root;
        $this->setThreshold(Level::getLevelAll());
        $this->rendererMap = new RendererMap();
    }

    /**
     * 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 RendererMap
     */
    public function getRendererMap()
    {
        return $this->rendererMap;
    }

    /**
     * Returns the root logger.
     * @return RootLogger
     */
    public function getRootLogger()
    {
        return $this->root;
    }

    /**
     * Returns the main threshold level.
     * @return Level
     */
    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(Level $level)
    {
        return ($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 *null*,
     * sets their additivity flag to *true* and sets the level
     * of the root logger to {@link LOGGER_LEVEL_DEBUG}.
     *
     * Existing loggers are not removed. They are just reset.
     *
     * This method should be used sparingly and with care as it will
     * block all logging until it is completed.
     */
    public function resetConfiguration()
    {
        $root = $this->getRootLogger();

        $root->setLevel(Level::getLevelDebug());
        $this->setThreshold(Level::getLevelAll());
        $this->shutDown();

        foreach ($this->loggers as $logger) {
            $logger->setLevel(null);
            $logger->setAdditivity(true);
            $logger->removeAllAppenders();
        }

        $this->rendererMap->reset();
        AppenderPool::clear();
    }

    /**
     * Sets the main threshold level.
     * @param Level $l
     */
    public function setThreshold(Level $threshold)
    {
        $this->threshold = $threshold;
    }

    /**
     * Shutting down a hierarchy will *safely* 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);
            }
        }
    }
}