PHP file iterator

CsvIterator.php

<?php

class CsvIterator extends FileIterator
{

    /**
     * @var string
     */
    protected $_delimiter;

    /**
     * @var string
     */
    protected $_enclosure;

    /**
     * @param string $filename
     * @param string $delimiter
     * @param string $enclosure
     */
    public function __construct($filename, $delimiter = ',', $enclosure = '"') {
        parent::__construct($filename);
        $this->_delimiter = $delimiter;
        $this->_enclosure = $enclosure;
    }

    protected function _getNextRow() {
        return fgetcsv($this->_handle, null, $this->_delimiter, $this->_enclosure);
    }

}

FileIterator.php

<?php

class FileIterator implements Iterator
{

    /**
     * @var resource
     */
    protected $_handle;

    /**
     * @var int
     */
    protected $_key;

    /**
     * @var mixed
     */
    protected $_row;

    /**
     * @param string $filename
     */
    public function __construct($filename) {
        if (($this->_handle = @fopen($filename, 'r')) === false) {
            throw new Exception('Unable to open file handle');
        }
    }

    public function __destruct() {
        fclose($this->_handle);
    }

    public function current() {
        return $this->_row;
    }

    public function next() {
        $this->_key++;
    }

    public function key() {
        return $this->_key;
    }

    public function valid() {
        $this->_row = $this->_getNextRow();
        return ($this->_row !== false);
    }

    public function rewind() {
        rewind($this->_handle);
        $this->_key = 0;
    }

    protected function _getNextRow() {
        return fgets($this->_handle);
    }

}