public function append($file, $data, $create = true, $modeBoolean = true)
    {
        // Preprocessing
        $file = $this->_preProcess($file);

        if (!$create && !$this->_resource_exists($file)) {
            throw new Doozr_Exception(
                'Could not append to file. The file: "'.$file.'" does not exist.'.
                'Current operation failed. Create file first or set parameter $create to TRUE'
            );
        }

        // exception for the case that the file|folder isn't writable
        if (!$this->_is_writable($file)) {
            throw new Doozr_Exception(
                'Could not append to file. Could not write given content to file: "'.$file.'" '.
                'Current operation failed. Check permissions.'
            );
        }

        // put the content to file
        $result = $this->_append($file, $data, $create);

        // transform result?
        if ($modeBoolean) {
            $result = ($result >= 0) ? true : false;
        }

        // return result of write operation
        return $result;
    }