CPhpMessageSource

protected function getMessageFile($category,$language)
{
    if(!isset($this->_files[$category][$language]))
    {
        if(($pos=strpos($category,'.'))!==false)
        {
            $extensionClass=substr($category,0,$pos);
            $extensionCategory=substr($category,$pos+1);
            // First check if there's an extension registered for this class.
            if(isset($this->extensionPaths[$extensionClass]))
                $this->_files[$category][$language]=Yii::getPathOfAlias($this->extensionPaths[$extensionClass]).DIRECTORY_SEPARATOR.$language.DIRECTORY_SEPARATOR.$extensionCategory.'.php';
            else
            {
                // No extension registered, need to find it.
                $class=new ReflectionClass($extensionClass);
                $this->_files[$category][$language]=dirname($class->getFileName()).DIRECTORY_SEPARATOR.'messages'.DIRECTORY_SEPARATOR.$language.DIRECTORY_SEPARATOR.$extensionCategory.'.php';
            }
        }
        else
            $this->_files[$category][$language]=$this->basePath.DIRECTORY_SEPARATOR.$language.DIRECTORY_SEPARATOR.$category.'.php';
    }
    return $this->_files[$category][$language];
}

public function init()
{
    parent::init();
    if($this->basePath===null)
        $this->basePath=Yii::getPathOfAlias('application.messages');
}

protected function loadMessages($category,$language)
{
    $messageFile=$this->getMessageFile($category,$language);

    if($this->cachingDuration>0 && $this->cacheID!==false && ($cache=Yii::app()->getComponent($this->cacheID))!==null)
    {
        $key=self::CACHE_KEY_PREFIX . $messageFile;
        if(($data=$cache->get($key))!==false)
            return unserialize($data);
    }

    if(is_file($messageFile))
    {
        $messages=include($messageFile);
        if(!is_array($messages))
            $messages=array();
        if(isset($cache))
        {
            $dependency=new CFileCacheDependency($messageFile);
            $cache->set($key,serialize($messages),$this->cachingDuration,$dependency);
        }
        return $messages;
    }
    else
        return array();
}