if($this->_config->getSqlLogger())

if($this->_hasLogger)

<?php                                                                                             
class Config                                                                                      
{                                                                                                 
    protected $_logger;                                                                           
    public function __construct()                                                                 
    {                                                                                             
        $this->_logger = new stdClass();
    }
    public function getLogger()
    {
        return $this->_logger;
    }
}

class Foo
{
    protected $_config = null;
    public function __construct()
    {
         $this->_config = new Config();
    }
    public function execute()
    {
         if($this->_config->getLogger()) {
         }
    }
}

class Bar
{
    protected $_config = null;
    protected $_loggerExists = false;
    public function __construct()
    {
         $this->_config = new stdClass();
         $this->_loggerExists = true;
    }
    public function execute()
    {
        if($this->_loggerExists) {

        }
    }
}

$f = new Foo();
$s = microtime(true);
for($i = 0; $i < 100; $i++) {
    $f->execute();
}
echo (microtime(true)-$s)."s\n";

$f = new Bar();
$s = microtime(true);
for($i = 0; $i < 100; $i++) {
    $f->execute();
}
echo (microtime(true)-$s)."s\n"

benny@benny-pc:~/code/php/wsnetbeans/Doctrine/trunk/tests$ php /tmp/boolvsmethod.php                
0.00055313110351562s                                                                                  
0.00025200843811035s                                                                                  
benny@benny-pc:~/code/php/wsnetbeans/Doctrine/trunk/tests$ php /tmp/boolvsmethod.php                
0.00051999092102051s                                                                                
0.00025200843811035s                                                                                
benny@benny-pc:~/code/php/wsnetbeans/Doctrine/trunk/tests$ php /tmp/boolvsmethod.php                
0.00036001205444336s                                                                                
0.00017309188842773s                                                                                
benny@benny-pc:~/code/php/wsnetbeans/Doctrine/trunk/tests$ php /tmp/boolvsmethod.php                
0.0005180835723877s                                                                                 
0.00025010108947754s