将Zend模型定义为Singleton

Question

I want to put my Zend Model as Singleton, so I have done this:

class Social_Model_DbTable_Dossier extends Zend_Db_Table_Abstract {

private static $_instance;

public static function GetInstance() {
    if (!self::$_instance instanceof self) {
        self::$_instance = new self();
    }
    return self::$_instance;
}

private function __construct() {
    // put normal constructor code.
    // it will only ever be called once
}}

I instantiate my model like so:

        $dossiercasModel =  Social_Model_DbTable_Dossier::GetInstance();

but this erreur is occured:

Fatal error: Access level to Social_Model_DbTable_Dossier::__construct() must be public (as in class Zend_Db_Table_Abstract)

when I put the constructor of the Model as public it works fine but this is inconsistent with the notion of singleton!

Answer 1

In the past I have gotten arround having to do this by creating a table broker that would serve up cached table instances, kind of a multiton.

a simple example

class My_TableManager{

   protected static $_instance;
   protected $_tableCache = array();

   protected function __construct(){

   }

   public static function getInstance(){
       if (!isset(self::$_instance)) self::$_instance = new self();
   }

   public function getTable($tableName){
        if (!array_key_exists($tableName, $this->_tableCache)){
            // you can do fun stuff here like name inflection
            // Im assuming that tables will be suffixed with _Table
            $tableClass = "My_".$tableName."_Table";
            $this->_tableCache[$tableName] = new $tableClass();
        }
        return $this->_tableCache[$tableName];
   }

   public static function get($tableName){
        return self::getInstance()->getTable($tableName);
   }
}

To use to get an instance of My_User_Table you would could:

$table = My_TableManager::get("My_User");

or

$table = My_TableManager::getInstnace()->getTable("My_Table");