Code analysis-which of the following php code can provide a detailed analysis? it is best to specify each line.

0;} publicstaticfunctionaddFlash ($ message) {if (! Strlen (trim ($ message) {thrownewException (& #39; Cannotinsertemptyflashmessage. & #39;) ;}self: initFlashes (); self: $ flashes [code analysis php

Final class Flash {

const FLASHES_KEY = '_flashes';private static $flashes = null;

Private function _ construct (){
}

public static function hasFlashes() {    self::initFlashes();    return count(self::$flashes) > 0;}public static function addFlash($message) {    if (!strlen(trim($message))) {        throw new Exception('Cannot insert empty flash message.');    }    self::initFlashes();    self::$flashes[] = $message;}public static function getFlashes() {    self::initFlashes();    $copy = self::$flashes;    self::$flashes = array();    return $copy;}private static function initFlashes() {    if (self::$flashes !== null) {        return;    }    if (!array_key_exists(self::FLASHES_KEY, $_SESSION)) {        $_SESSION[self::FLASHES_KEY] = array();    }    self::$flashes = &$_SESSION[self::FLASHES_KEY];}

}

?>