src/Renderers/RendererMap.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\Renderers;

/**
 * Manages defined renderers and determines which renderer to use for a given
 * input.
 *
 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
 * @since 0.3
 */
class RendererMap
{
    /**
     * Maps class names to appropriate renderers.
     * @var array
     */
    private $map = array();

    /**
     * The default renderer to use if no specific renderer is found.
     * @var RendererInterface
     */
    private $defaultRenderer;

    public function __construct()
    {
        // Set default config
        $this->reset();
    }

    /**
     * Adds a renderer to the map.
     *
     * If a renderer already exists for the given <var>$renderedClass</var> it
     * will be overwritten without warning.
     *
     * @param string $renderedClass The name of the class which will be
     *     rendered by the renderer.
     * @param string $renderingClass The name of the class which will
     *     perform the rendering.
     */
    public function addRenderer($renderedClass, $renderingClass)
    {
        if (class_exists($renderingClass)) {
            $renderer = new $renderingClass();
        } else {
            // Try to find renderer in the default namespace
            $namespaced = "Apache\\Log4php\\Renderers\\$renderingClass";
            if (class_exists($namespaced)) {
                $renderer = new $namespaced();
            }
        }

        if (!isset($renderer)) {
            trigger_error(
                "log4php: Failed adding renderer. Rendering class [$renderingClass] not found.",
                E_USER_WARNING
            );

            return;
        }

        // Check the class implements the right interface
        if (!($renderer instanceof RendererInterface)) {
            trigger_error(
                "log4php: Failed adding renderer. " .
                "Rendering class [$renderingClass] does not implement RendererInterface.",
                E_USER_WARNING
            );

            return;
        }

        // Convert to lowercase since class names in PHP are not case sensitive
        $renderedClass = strtolower($renderedClass);

        $this->map[$renderedClass] = $renderer;
    }

    /**
     * Sets a custom default renderer class.
     *
     * TODO: there's code duplication here. This method is almost identical to
     * addRenderer(). However, it has custom error messages so let it sit for
     * now.
     *
     * @param string $renderingClass The name of the class which will
     * 		perform the rendering.
     */
    public function setDefaultRenderer($renderingClass)
    {
        // Check the class exists
        if (!class_exists($renderingClass)) {
            trigger_error(
                "log4php: Failed setting default renderer. Rendering class [$renderingClass] not found.",
                E_USER_WARNING
            );

            return;
        }

        // Create the instance
        $renderer = new $renderingClass();

        // Check the class implements the right interface
        if (!($renderer instanceof RendererInterface)) {
            trigger_error(
                "log4php: Failed setting default renderer. " .
                "Rendering class [$renderingClass] does not implement RendererInterface.",
                E_USER_WARNING
            );

            return;
        }

        $this->defaultRenderer = $renderer;
    }

    /**
     * Returns the default renderer.
     * @var RendererInterface
     */
    public function getDefaultRenderer()
    {
        return $this->defaultRenderer;
    }

    /**
     * Finds the appropriate renderer for the given <var>input</var>, and
     * renders it (i.e. converts it to a string).
     *
     * @param  mixed  $input Input to render.
     * @return string The rendered contents.
     */
    public function findAndRender($input)
    {
        if ($input === null) {
            return null;
        }

        // For objects, try to find a renderer in the map
        if (is_object($input)) {
            $renderer = $this->getByClassName(get_class($input));
            if (isset($renderer)) {
                return $renderer->render($input);
            }
        }

        // Fall back to the default renderer
        return $this->defaultRenderer->render($input);
    }

    /**
     * Returns the appropriate renderer for a given object.
     *
     * @param  mixed             $object
     * @return RendererInterface Or null if none found.
     */
    public function getByObject($object)
    {
        if (!is_object($object)) {
            return null;
        }

        return $this->getByClassName(get_class($object));
    }

    /**
     * Returns the appropriate renderer for a given class name.
     *
     * If no renderer could be found, returns NULL.
     *
     * @param  string               $class
     * @return LoggerRendererObject Or null if not found.
     */
    public function getByClassName($class)
    {
        for (; !empty($class); $class = get_parent_class($class)) {
            $class = strtolower($class);
            if (isset($this->map[$class])) {
                return $this->map[$class];
            }
        }

        return null;
    }

    /** Empties the renderer map. */
    public function clear()
    {
        $this->map = array();
    }

    /** Resets the renderer map to it's default configuration. */
    public function reset()
    {
        $this->defaultRenderer = new DefaultRenderer();
        $this->clear();
        $this->addRenderer('Exception', 'ExceptionRenderer');
    }
}