CFilterChain

public function __construct($controller,$action)
{
    $this->controller=$controller;
    $this->action=$action;
}

public static function create($controller,$action,$filters)
{
    $chain=new CFilterChain($controller,$action);

    $actionID=$action->getId();
    foreach($filters as $filter)
    {
        if(is_string($filter))  // filterName [+|- action1 action2]
        {
            if(($pos=strpos($filter,'+'))!==false || ($pos=strpos($filter,'-'))!==false)
            {
                $matched=preg_match("/\b{$actionID}\b/i",substr($filter,$pos+1))>0;
                if(($filter[$pos]==='+')===$matched)
                    $filter=CInlineFilter::create($controller,trim(substr($filter,0,$pos)));
            }
            else
                $filter=CInlineFilter::create($controller,$filter);
        }
        else if(is_array($filter))  // array('path.to.class [+|- action1, action2]','param1'=>'value1',...)
        {
            if(!isset($filter[0]))
                throw new CException(Yii::t('yii','The first element in a filter configuration must be the filter class.'));
            $filterClass=$filter[0];
            unset($filter[0]);
            if(($pos=strpos($filterClass,'+'))!==false || ($pos=strpos($filterClass,'-'))!==false)
            {
                $matched=preg_match("/\b{$actionID}\b/i",substr($filterClass,$pos+1))>0;
                if(($filterClass[$pos]==='+')===$matched)
                    $filterClass=trim(substr($filterClass,0,$pos));
                else
                    continue;
            }
            $filter['class']=$filterClass;
            $filter=Yii::createComponent($filter);
        }

        if(is_object($filter))
        {
            $filter->init();
            $chain->add($filter);
        }
    }
    return $chain;
}

public function insertAt($index,$item)
{
    if($item instanceof IFilter)
        parent::insertAt($index,$item);
    else
        throw new CException(Yii::t('yii','CFilterChain can only take objects implementing the IFilter interface.'));
}

public function run()
{
    if($this->offsetExists($this->filterIndex))
    {
        $filter=$this->itemAt($this->filterIndex++);
        Yii::trace('Running filter '.($filter instanceof CInlineFilter ? get_class($this->controller).'.filter'.$filter->name.'()':get_class($filter).'.filter()'),'system.web.filters.CFilterChain');
        $filter->filter($this);
    }
    else
        $this->controller->runAction($this->action);
}