PHP yield example to open big file and stream line by line

PHP yield to stream big file

<?php

/**
 * Class File
 */
class File
{

    private $fileName;
    private $file;

    public function __construct($fileName)
    {
        $this->fileName = $fileName;
        $this->openDb();
    }

    /**
     * @return \Generator
     * read line by line use less memory
     */
    public function getLine()
    {
        while (($line = fgets($this->file)) !== false) {

            if (!empty($line)) {
                yield $line;
            } else {
                $this->closeDb();
            }

        }
    }

    private function openDb()
    {
        $this->file = fopen($this->getFileName(), 'r');
    }

    private function closeDb()
    {
        fclose($this->file);
    }
    
    public function getFileName()
    {
        return $this->fileName;
    }
    
    public function getFile()
    {
        return $this->file;
    }

}