class Twig_TokenParserBroker

class Twig_TokenParserBroker implements Twig_TokenParserBrokerInterface {
  protected $parser;
  protected $parsers = array();
  protected $brokers = array();

  /**
   * Constructor.
   *
   * @param array|Traversable $parsers A Traversable of Twig_TokenParserInterface instances
   * @param array|Traversable $brokers A Traversable of Twig_TokenParserBrokerInterface instances
   */
  public function __construct($parsers = array(), $brokers = array()) {
    foreach ($parsers as $parser) {
      if (!$parser instanceof Twig_TokenParserInterface) {
        throw new Twig_Error('$parsers must a an array of Twig_TokenParserInterface');
      }
      $this->parsers[$parser
        ->getTag()] = $parser;
    }
    foreach ($brokers as $broker) {
      if (!$broker instanceof Twig_TokenParserBrokerInterface) {
        throw new Twig_Error('$brokers must a an array of Twig_TokenParserBrokerInterface');
      }
      $this->brokers[] = $broker;
    }
  }

  /**
   * Adds a TokenParser.
   *
   * @param Twig_TokenParserInterface $parser A Twig_TokenParserInterface instance
   */
  public function addTokenParser(Twig_TokenParserInterface $parser) {
    $this->parsers[$parser
      ->getTag()] = $parser;
  }

  /**
   * Adds a TokenParserBroker.
   *
   * @param Twig_TokenParserBroker $broker A Twig_TokenParserBroker instance
   */
  public function addTokenParserBroker(Twig_TokenParserBroker $broker) {
    $this->brokers[] = $broker;
  }

  /**
   * Gets a suitable TokenParser for a tag.
   *
   * First looks in parsers, then in brokers.
   *
   * @param string $tag A tag name
   *
   * @return null|Twig_TokenParserInterface A Twig_TokenParserInterface or null if no suitable TokenParser was found
   */
  public function getTokenParser($tag) {
    if (isset($this->parsers[$tag])) {
      return $this->parsers[$tag];
    }
    $broker = end($this->brokers);
    while (false !== $broker) {
      $parser = $broker
        ->getTokenParser($tag);
      if (null !== $parser) {
        return $parser;
      }
      $broker = prev($this->brokers);
    }
    return null;
  }
  public function getParsers() {
    return $this->parsers;
  }
  public function getParser() {
    return $this->parser;
  }
  public function setParser(Twig_ParserInterface $parser) {
    $this->parser = $parser;
    foreach ($this->parsers as $tokenParser) {
      $tokenParser
        ->setParser($parser);
    }
    foreach ($this->brokers as $broker) {
      $broker
        ->setParser($parser);
    }
  }

}