LoaderChain.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\Validator\Mapping\Loader;

use Symfony\Component\Validator\Exception\MappingException;
use Symfony\Component\Validator\Mapping\ClassMetadata;

/**
 * Calls multiple LoaderInterface instances in a chain
 *
 * This class accepts multiple instances of LoaderInterface to be passed to the
 * constructor. When loadClassMetadata() is called, the same method is called
 * in <em>all</em> of these loaders, regardless of whether any of them was
 * successful or not.
 *
 * @author Bernhard Schussek <bschussek@gmail.com>
 */
class LoaderChain implements LoaderInterface {
  protected $loaders;

  /**
   * Accepts a list of LoaderInterface instances
   *
   * @param LoaderInterface[] $loaders An array of LoaderInterface instances
   *
   * @throws MappingException If any of the loaders does not implement LoaderInterface
   */
  public function __construct(array $loaders) {
    foreach ($loaders as $loader) {
      if (!$loader instanceof LoaderInterface) {
        throw new MappingException(sprintf('Class %s is expected to implement LoaderInterface', get_class($loader)));
      }
    }
    $this->loaders = $loaders;
  }

  /**
   * {@inheritDoc}
   */
  public function loadClassMetadata(ClassMetadata $metadata) {
    $success = false;
    foreach ($this->loaders as $loader) {
      $success = $loader
        ->loadClassMetadata($metadata) || $success;
    }
    return $success;
  }

}