Design patterns Multiton Pool of Singletons (PHP example)
Example
Multiton can be used as a container for singletons. This is Multiton implementation is a combination of Singleton and Pool patterns.
This is an example of how common Multiton abstract Pool class can be created:
abstract class MultitonPoolAbstract
{
/**
* @var array
*/
protected static $instances = [];
final protected function __construct() {}
/**
* Get class name of lately binded class
*
* @return string
*/
final protected static function getClassName()
{
return get_called_class();
}
/**
* Instantiates a calling class object
*
* @return static
*/
public static function getInstance()
{
$className = static::getClassName();
if( !isset(self::$instances[$className]) ) {
self::$instances[$className] = new $className;
}
return self::$instances[$className];
}
/**
* Deletes a calling class object
*
* @return void
*/
public static function deleteInstance()
{
$className = static::getClassName();
if( isset(self::$instances[$className]) )
unset(self::$instances[$className]);
}
/*-------------------------------------------------------------------------
| Seal methods that can instantiate the class
|------------------------------------------------------------------------*/
final protected function __clone() {}
final protected function __sleep() {}
final protected function __wakeup() {}
}
This way we can instantiate a various Singleton pools.
