/**
* 取得对应分类下面商品的总数，用于分页显示
*
* @return int 商品总数
*
* @param int $categoryId 分类的ID
* @param int $level 取得多少层，子分类有可能很深，我们只取有限层次
* @param string $systemTag 系统标记
* @param int $ttl 缓存时间
*/
public function countGoodsArray($categoryId, $level, $systemTag, $ttl = 0)
{
// 参数验证
$validator = new Validator(array('categoryId' => $categoryId, 'level' => $level, 'systemTag' => $systemTag, 'ttl' => $ttl));
$categoryId = $validator->digits()->min(0)->validate('categoryId');
$level = $validator->required()->digits()->min(1)->validate('level');
$systemTag = $validator->validate('systemTag');
$ttl = $validator->digits()->min(0)->validate('ttl');
$this->validate($validator);
$childrenIdArray = $this->fetchCategoryChildrenIdArray($categoryId, $level, $ttl);
$childrenIdArray[] = $categoryId;
// 加入父节点
$queryCondArray = array();
$queryCondArray[] = array('is_delete = 0 AND is_on_sale = 1 AND is_alone_sale = 1');
// 构建 SQL 的 in 语句， cat_id in (100,20,30)
$queryCondArray[] = array(QueryBuilder::buildInCondition('cat_id', $childrenIdArray, \PDO::PARAM_INT));
if (!empty($systemTag)) {
$queryCondArray[] = array('system_tag_list like ? ', '%' . Utils::makeTagString(array($systemTag)) . '%');
}
$dataMapper = new DataMapper('goods');
return $dataMapper->count(QueryBuilder::buildAndFilter($queryCondArray), null, $ttl);
}