Attachment/AttachmentHandler.php
protected function getFileKey($key)
    {
        $key = (string) $key;
        if (!array_key_exists($key, $this->fileKeys))
        {
            $this->fileKeys[$key] = new FileKey($key);
        }
        
        return $this->fileKeys[$key];
    }
protected function getFileKey($key)
    {
        $key = (string) $key;
        if (!array_key_exists($key, $this->fileKeys))
        {
            $this->fileKeys[$key] = new FileKey($key);
        }
        
        return $this->fileKeys[$key];
    }
protected function getFileKey ( $ key ) { $ key = ( string ) $ key ; if ( ! array_key_exists ( $ key , $ this -> fileKeys ) ) { $ this -> fileKeys [ $ key ] = new FileKey ( $ key ) ; } return $ this -> fileKeys [ $ key ] ; }
Convert an existing string key to a FileKey object for further usage.

@throws InvalidKeyException              if the key cannot be parsed

@param string $key

@return FileKey
Convert an existing string key to a FileKey object for further usage .