Count lines of code in folder - PHP Class

    define('SHOW_DETAILS', true);

    class Folder {

        var $name;
        var $path;
        var $folders;
        var $files;
        var $exclude_extensions;
        var $exclude_files;
        var $exclude_folders;


        function Folder($path) {
            $this -> path       = $path;
            $this -> name       = array_pop( array_filter( explode(DIRECTORY_SEPARATOR, $path) ) );
            $this -> folders    = array();
            $this -> files      = array();
            $this -> exclude_extensions = array('gif', 'jpg', 'jpeg', 'png', 'tft', 'bmp', 'rest-of-the-file-extensions-to-exclude');
            $this -> exclude_files      = array('count_lines.php', 'rest-of-the-files-to-exclude');
            $this -> exclude_folders     = array('_private', '_vti_bin', '_vti_cnf', '_vti_log', '_vti_pvt', '_vti_txt', 'rest-of-the-folders-to-exclude');
        }

        function count_lines() {
            if( defined('SHOW_DETAILS') ) print "";
            $total_lines = 0;
            $this -> get_contents();
            foreach($this -> files as $file) {
                if( in_array($file -> ext, $this -> exclude_extensions) || in_array($file -> name, $this -> exclude_files) ) {
                    if( defined('SHOW_DETAILS') ) print "#---Skipping File: {$file -> name};\n";
                    continue;
                }
                $total_lines += $file -> get_num_lines();
            }
            foreach($this -> folders as $folder) {
                if( in_array($folder -> name, $this -> exclude_folders) ) {
                    if( defined('SHOW_DETAILS') ) print "#Skipping Folder: {$folder -> name};\n";
                    continue;
                }
                $total_lines += $folder -> count_lines();
            }
            if( defined('SHOW_DETAILS') ) print "";
            return $total_lines;
        }

        function get_contents() {
            $contents = $this -> _get_contents();
            foreach($contents as $key => $value) {
                if( $value['type'] == 'Folder' ) {
                    $this -> folders[] = new Folder($value['item']);
                } else {
                    $this -> files[]   = new File  ($value['item']);
                }
            }
        }

        function _get_contents() {
            $folder = $this -> path;
            if( !is_dir($folder) ) {
                return array();
            }
            $return_array = array();
            $count        = 0;
            if( $dh = opendir($folder) ) {
                while( ($file = readdir($dh)) !== false ) {
                    if( $file == '.' || $file == '..' ) continue;
                    $return_array[$count]['item']   = $folder .$file .(is_dir($folder .$file) ? DIRECTORY_SEPARATOR : '');
                    $return_array[$count]['type']   = is_dir($folder .$file) ? 'Folder' : 'File';
                    $count++;
                }
                closedir($dh);
            }
            return $return_array;
        }

    } // Class

    class File {

        var $name;
        var $path;
        var $ext;


        function File($path) {
            $this -> path = $path;
            $this -> name = basename($path);
            $this -> ext  = array_pop( explode('.', $this -> name) );
        }

        function get_num_lines() {
            $count_lines = count(file($this -> path));
            if( defined('SHOW_DETAILS') ) print "";
            return $count_lines;
        }

    } // Class