symfony/src/Symfony/Component/HttpKernel/DependencyInjection/Extension.php

<?php

namespace Symfony\Component\HttpKernel\DependencyInjection;

use Symfony\Component\DependencyInjection\Extension\ExtensionInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Container;

/*
 * This file is part of the Symfony framework.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * This source file is subject to the MIT license that is bundled
 * with this source code in the file LICENSE.
 */

/**
 * Provides useful features shared by many extensions.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
abstract class Extension implements ExtensionInterface
{
    private $classes = array();

    /**
     * Gets the classes to cache.
     *
     * @return array An array of classes
     */
    public function getClassesToCompile()
    {
        return $this->classes;
    }

    /**
     * Adds classes to the class cache.
     *
     * @param array $classes An array of classes
     */
    public function addClassesToCompile(array $classes)
    {
        $this->classes = array_merge($this->classes, $classes);
    }

    /**
     * Returns the base path for the XSD files.
     *
     * @return string The XSD base path
     */
    public function getXsdValidationBasePath()
    {
        return false;
    }

    /**
     * Returns the namespace to be used for this extension (XML namespace).
     *
     * @return string The XML namespace
     */
    public function getNamespace()
    {
        return 'http://example.org/schema/dic/'.$this->getAlias();
    }

    /**
     * Returns the recommended alias to use in XML.
     *
     * This alias is also the mandatory prefix to use when using YAML.
     *
     * This convention is to remove the "Extension" postfix from the class
     * name and then lowercase and underscore the result. So:
     *
     *     AcmeHelloExtension
     *
     * becomes
     *
     *     acme_hello
     *
     * This can be overridden in a sub-class to specify the alias manually.
     *
     * @return string The alias
     */
    public function getAlias()
    {
        $className = get_class($this);
        if (substr($className, -9) != 'Extension') {
            throw new \BadMethodCallException('This extension does not follow the naming convention; you must overwrite the getAlias() method.');
        }
        $classBaseName = substr(strrchr($className, '\\'), 1, -9);

        return Container::underscore($classBaseName);
    }
}