protected function _setAccessMode($accessMode)
    {
        // Check for valid access mode
        $accessMode = substr(strtolower($accessMode), 0, 1);
        if ($accessMode!='w' && $accessMode!='a') {
            throw new Zend_Log_Adapter_Exception("Illegal access mode specified.  Specify 'a' for append or 'w' for overwrite.");
        }
        $this->_accessMode = $accessMode;

        return true;
    }