class.db.php

<?php
namespace Module\DB;

/**
 * Implements a singleton database class
 *
 * This abstract class is to ensure that only one PDO instance is used. You get
 * a instance of the database with:
 *
 * ### Usage
 *
 * <code>
 *   \Module\DB\DB::$dbhost = 'localhost';
 *   \Module\DB\DB::$dbname = 'db';
 *   \Module\DB\DB::$dbuser = 'username';
 *   \Module\DB\DB::$dbpass = 'itsmeopenup';
 *   $db = \Module\DB\DB::getInstance();
 * </code>
 *
 * ### Changelog
 *
 * ## Version 1.12
 * * Added the date section to the documentation
 *
 * @date August 13, 2014
 * @author Jaime A. Rodriguez <hi.i.am.jaime@gmail.com>
 * @version 1.2
 * @license  http://opensource.org/licenses/MIT
 */
abstract class DB {

	/**
	 * PDO The single instance is stored here.
	 * @private
	 */
	private static $instance = NULL;

	/**
	 * string The database host
	 */
	public static $dbhost = DBHOST;

	/**
	 * string The database name
	 */
	public static $dbname = DBNAME;

	/**
	 * string The database user
	 */
	public static $dbuser = DBUSER;

	/**
	 * string The database password
	 */
	public static $dbpass = DBPASS;

	/**
	* Sets constructor to private, prevents new instances
	*/
	private function __construct() {}

	/**
	* Sets __clone to private, prevents clones
	*/
	private function __clone(){}

	/**
	* Gets the DB instance or creates an initial connection
	*
	* @return object (PDO)
	*/
	public static function getInstance() {
		if (!self::$instance) {
			self::$instance = new \PDO("mysql:host=" . self::$dbhost . ";dbname=" . self::$dbname, self::$dbuser, self::$dbpass);
			self::$instance-> setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
			self::$instance-> setAttribute(\PDO::ATTR_EMULATE_PREPARES, false);
		}
		
		return self::$instance;
	}
}