php 回调函数

publicfunction transaction(Closure $callback){

    $this->beginTransaction();

    // We'll simply execute the given callback within a try / catch block

    // and if we catch any exception we can rollback the transaction

    // so that none of the changes are persisted to the database.

    try

    {

        $result = $callback($this);

        $this->commit();

    }

    // If we catch an exception, we will roll back so nothing gets messed

    // up in the database. Then we'll re-throw the exception so it can

    // be handled how the developer sees fit for their applications.

    catch(Exception $e)

    {

        $this->rollBack();

        throw $e;

    }