singleton

<?php

class sng
{
	public $data = array();
	
	public $objects = array();
	
	private static $instance;
	
	public function __construct()
	{
	}
	
	public function __clone()
	{
		throw new exception( "Cloning is not allowed" );
	}
	
	public static function singleton()
	{
		if( !isset( self::$instance ) )
		{
			$c = __CLASS__;
			self::$instance = new $c;
		}
		
		return self::$instance;
	}
	
	public function registerClass( $key , $classname )
	{
		$this->objects[$key] = new $classname;
	}
	
	public function useClass( $key )
	{
		return $this->objects[$key];
	}
	
	public function putData( $value )
	{
		$this->data[] = $value;
		
		return count($this->data)-1;
	}
	
	public function getData( $key )
	{
		if( is_numeric( $key ) )
		{
			return $this->data[$key];
		}
		else
		{
			throw new exception( "Key value is not valid (not an integer)" );
		}
	}
}

class testclass
{
	public function somefunction()
	{
		echo "Foo Bar";
	}
}

$test = sng::singleton();
$test->registerClass('tc','testclass');
$test->useClass('tc')->somefunction();
?>

<?php
 
class sng
{
	public $data = array();
 
	public $objects = array();
 
	private static $instance;
 
	public function __construct()
	{
	}
 
	public function __clone()
	{
		throw new exception( "Cloning is not allowed" );
	}
 
	public static function singleton()
	{
		if( !isset( self::$instance ) )
		{
			$c = __CLASS__;
			self::$instance = new $c;
		}
 
		return self::$instance;
	}
 
	public function registerClass( $key , $classname )
	{
		$this->objects[$key] = new $classname;
	}
 
	public function useClass( $key )
	{
		return $this->objects[$key];
	}
 
	public function putData( $value )
	{
		$this->data[] = $value;
 
		return count($this->data)-1;
	}
 
	public function getData( $key )
	{
		if( is_numeric( $key ) )
		{
			return $this->data[$key];
		}
		else
		{
			throw new exception( "Key value is not valid (not an integer)" );
		}
	}
}
 
class testclass
{
	public function somefunction()
	{
		echo "Foo Bar";
	}
}
 
$test = sng::singleton();
$test->registerClass('tc','testclass');
$test->useClass('tc')->somefunction();
?>

$test = sng::singleton()->registerclass('tc','testclass')->useClass('tc');
$test->somefunction();

$test = sng::singleton()->registerclass('tc','testclass')->useClass('tc');
$test->somefunction();