Public variable in singleton do not survive

roman · 11-05-2010, 03:02 PM

Hi,

I am trying to use singleton in my application. I believed singleton object can hold public variables to be used at any place of my code. But it does not work... Within the same request the singleton loses public vars content. Thanks to anyone who can help me :)

PHP Code:


			


// singleton to keep errors

class Errors {

    

    private static $_instance;

    public $errorList;

    

    private function __construct () {

        $this->errorList = array();

    }

    

    public static function getInstance() {

        if (empty(self::$_instance))

            self::$_instance = new Errors ();

        return self::$_instance;

    }

    

    public function addError ($error) {

        $this->errorList[] = $error;

    }                

}



// when I use the singleton first time, it holds the public value of errorList

$err = Errors::getInstance();

$err->addError('some error');

print_r ($err->errorList);



// ... some code here



// when I get the instance again within the same request, the errorList seems to have lost it's value ('some error')

$err = Errors::getInstance();

print_r ($err->errorList);

wGEric · 11-09-2010, 10:44 PM

Are you replacing the contents of $err->errorList anywhere between those two print_r()s? I ran your code exactly as you posted it and some error was showing twice.

roman · 11-10-2010, 07:21 PM

Hi Eric,

I don't change the $err content meanwhile, it is just empty when I try to print_r() it...

jgetner · 11-14-2010, 02:38 PM

try this on for size..

PHP Code:


			

class Errors
{
   private $errorsList = array();

   private static $instance;

   private function __construct()
   {
   }
   
   public static function Instance()
   {
     if(!(self::$instance instanceof self)
     {
        self::$instance = new self;
     }

     return self::$instance;
   }

  public static function AddError($id , $error)
  {
    if(!(isset(self::$instance->errorsList[$id])
    {
       return self::$instance->errorsList[$id] = $error;
    }

    elseif(isset(self::$instance->errorsList[$id])
    {
       return self::$instance->errorsList[$id] = $error;
    }

    else
    {
      throw new Exception('The Current Error Value Could Not Be Located');
    }

    return(FALSE);
  }

  public static function GetError($id)
  {
    if(isset(self::$instance->errorsList[$id])
    {
       return self::$instance->errorsList[$id];
    }
    
    else
    {
      return(FALSE);
    }
  }
}

example....

$error = Errors::Instance();
$errors->AddError('userError' , 'Your Have An Error');

print_r($errors->GetError('userError'));