<?php
/*=====================================================================*\
|| ###################################################################
|| # Blue Static ISSO Framework [#]issoversion[#]
|| # Copyright Š2002-[#]year[#] Blue Static
|| #
|| # This program is free software; you can redistribute it and/or modify
|| # it under the terms of the GNU General Public License as published by
|| # the Free Software Foundation; version [#]gpl[#] of the License.
|| #
|| # This program is distributed in the hope that it will be useful, but
|| # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|| # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|| # more details.
|| #
|| # You should have received a copy of the GNU General Public License along
|| # with this program; if not, write to the Free Software Foundation, Inc.,
|| # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
|| ###################################################################
\*=====================================================================*/

/**
* System loader (Loader.php)
*
* @package	ISSO
*/

/**
* System Loader
*
* This class contains static methods that are used to create new registers and
* load modules.
*
* @author		Blue Static
* @copyright	Copyright Š2002 - [#]year[#], Blue Static
* @version		$Revision$
* @package		ISSO
* 
*/
class BSLoader
{
	/**
	* Singleton instance
	* @var	object
	*/
	private static $instance;
	
	/**
	* Array of all the registers
	* @var	array
	*/
	private $registers = array();
	
	/**
	* The main register
	* @var	object
	*/
	private $main;
	
	// ###################################################################
	/**
	* Constructor
	*/
	private function __construct() {}
	
	// ###################################################################
	/**
	* Returns the shared instance of the BSLoader singleton class.
	*
	* @return	object	The BSLoader shared instance
	*/
	private function SharedInstance()
	{
		if (!self::$instance)
		{
			self::$instance = new BSLoader;
		}
		return self::$instance;
	}
	
	// ###################################################################
	/**
	* Creates a new BSRegister instance and returns it.
	*
	* @return	object	New register
	*/
	public static function NewRegister()
	{
		require_once('ISSO/Register.php');
		
		self::SharedInstance()->registers[] = new BSRegister();
		
		return end(self::SharedInstance()->registers);
	}
	
	// ###################################################################
	/**
	* Returns the array of all the registers
	*
	* @return	array	The array of all the registers
	*/
	public static function GetAllRegisters()
	{	
		return self::SharedInstance()->registers;
	}
	
	// ###################################################################
	/**
	* Sets the main register
	*
	* @param	object	New main register
	*/
	public static function SetRegister($register)
	{
		if (get_class($register) != 'BSRegister')
		{
			throw new Exception('BSLoader::SetRegister() was not passed a BSRegister object');
		}
		
		self::SharedInstance()->main = $register;
	}
	
	// ###################################################################
	/**
	* Gets the main register if no argument is passed, or an arbitrary
	* one if the index of a register is passed.
	*
	* @param	integer	Register index
	*
	* @return	object	Specified register
	*/
	public static function &GetRegister($index = null)
	{
		if (is_null($index))
		{
			if (!isset(self::SharedInstance()->main))
			{
				throw new Exception('Cannot fetch the main register because it has not been set with BSLoader::SetRegister()');
			}
			return self::SharedInstance()->main;
		}
		else
		{
			if (!isset(self::SharedInstance()->registers["$index"]))
			{
				throw new Exception('Invalid register index passed to BSLoader::GetRegister()');
			}
			return self::SharedInstance()->registers["$index"];
		}
	}
	
	// ###################################################################
	/**
	* Loads the specified module.
	*
	* @param	string	Module name
	*
	* @return	object	Instantiated module
	*/
	public static function LoadModule($name)
	{
		if (!file_exists("ISSO/$name.php"))
		{
			throw new Exception('Specified module does not exist');
		}
		
		require_once("ISSO/$name.php");
		
		$class = "BS$name";
		
		if (!class_exists($class))
		{
			throw new Exception('Specifed module does not conform to the ISSO specification, or the class is missing');
		}
		
		return new $class;
	}
}

/*=====================================================================*\
|| ###################################################################
|| # $HeadURL$
|| # $Id$
|| ###################################################################
\*=====================================================================*/
?>