How to wait till page load selenium Java.

 public void waitTillDocumentStateReady()

{
    LocalDateTime now = LocalDateTime.now();
    while (LocalDateTime.now().isBefore(now.plusSeconds(20))) {
        while (!((JavascriptExecutor) driver.getDriver()).executeScript("return document.readyState").equals("complete")) {
            driver.sleep(1);
        }
    }
}