protected function formatEra($pattern,$date)
	{
		$era=$date['year']>0 ? 1 : 0;
		switch($pattern)
		{
			case 'G':
			case 'GG':
			case 'GGG':
				return $this->_locale->getEraName($era,'abbreviated');
			case 'GGGG':
				return $this->_locale->getEraName($era,'wide');
			case 'GGGGG':
				return $this->_locale->getEraName($era,'narrow');
			default:
				throw new CException(Yii::t('yii','The pattern for era must be "G", "GG", "GGG", "GGGG" or "GGGGG".'));
		}
	}