PDO Transaction manager

example.php

class Model {
	...
	
	private function startTransaction() {
		$transactionManager = new TransactionManager($this->pdo);
		$transactionManager->beginTransaction();
		return $transactionManager;
	}
	
	public function save($data) {
		try {
			$transactionManager = $this->startTransaction();
			...
			$transactionManager->commit();
		} catch(\Exception) {
			$transactionManager->rollback();
		}
	}
}

TransactionManager.php

<?php

/********************************************************************\
/*  This file is part of the FREGIS System (http://www.fregis.cz)     \
/*  Copyright (c) 2012 Karel Hák, Martin Jelič, Jakub Kocourek         \
/*                                                                     /
/*  @license Use it as you want                                       /
/********************************************************************/

namespace Fregis\Database;

/**
 * @author Karel Hák <karel.hak@fregis.cz>
 */
class TransactionManager extends \Nette\Object {
	/** @var \PDO */
	private $pdo;
	private $inTransaction;
	
	public function __construct(\PDO $pdo) {
		$this->pdo = $pdo;
	}
	
	public function beginTransaction() { 
		$this->inTransaction = $this->pdo->inTransaction();
		
		if(!$this->inTransaction) { 
			return $this->pdo->beginTransaction(); 
		} 
     }
	 
	function commit() { 
		if(is_null($this->inTransaction)) {
			throw new \Nette\InvalidStateException('beginTransaction was not called before commit');
		}
		if(!$this->inTransaction && $this->pdo->inTransaction()) {
			$this->pdo->commit();
		}
		$this->inTransaction = null;
    } 

    function rollback() { 
		if(is_null($this->inTransaction)) {
			throw new \Nette\InvalidStateException('beginTransaction was not called before commit');
		}
		
		if(!$this->inTransaction && $this->pdo->inTransaction()) {
			$this->pdo->rollBack();
		}
		$this->inTransaction = null;
    }
}