Strict standards warning: Singleton implementation with PHP - php

Question

I have created a logger as a singleton for my PHP application with Zend framework.
Implementation is pretty straight-forward:
class Logger
{
protected static $_logger;
private function __construct()
{
// initialize logger
$writer = new Zend_Log_Writer_Stream(LOG_PATH);
$this->_logger = new Zend_Log($writer);
}
public static function getLogger()
{
if (null === self::$_logger)
{
self::$_logger = new self();
}
return self::$_logger;
}
public static function Log($message, $logType)
{
if ($logType <= LOG_MAX)
{
$logger = self::getLogger();
$logger->_logger->log($message, $logType);
}
}
}
To ad an entry to the log, I just call static method:
Logger::Log('message', Zend_Log::ERR);
Logger works as supposed to, but since I have upgraded my PHP version to 5.4.3 I get an error:
Strict standards: Accessing static property Logger::$_logger as non static in Z:\Software\PHP\EA Game\application\classes\Logger.php on line 28
Line 28 is in function __construct(): $this->_logger = new Zend_Log($writer);
I can always disable E_STRICT, but it is not a preferable option.
I would like to implement Singleton pattern without getting Strict standards warning.
I would be grateful if some could point me in the right direction to implementing Singleton pattern without getting String standards warning.
EDIT:
I used jValdrons advice and replaced $this->_logger to self::$_logger.
I still was getting strict standards warning and I changed Log function to be as follows:
public static function Log($message, $logType)
{
if ($logType <= LOG_MAX)
{
self::getLogger()->log($message, $logType);
}
}
But now I have another problem.
Code does not throw Strict standards warning, but it does not works as supposed to.
I have 2 separate loggers, 1 for application and 1 for crons.
Basically it's just the same code:
2 static variables:
protected static $_logger;
protected static $_cronLogger;
constructor initializes both of them:
private function __construct()
{
// initialize all loggers
$writer = new Zend_Log_Writer_Stream(LOG_PATH);
self::$_logger = new Zend_Log($writer);
$writerCron = new Zend_Log_Writer_Stream(CRON_LOG_PATH);
self::$_cronLogger = new Zend_Log($writerCron);
}
and 2 methods GetCronLogger() and LogCron():
public static function getCronLogger()
{
if (null === self::$_cronLogger)
{
self::$_cronLogger = new self();
}
return self::$_cronLogger;
}
public static function LogCron($message, $logType)
{
if ($logType <= CRON_LOG_MAX)
{
self::getCronLogger()->log($message, $logType);
}
}
But now self::getCronLogger()->log($message, $logType); calls my method Log(), not Zend_log->log() and it will always add records to my main logger, not crons logger.
Am I missing something or calling something in incorrect way?

Answer 1

You're accessing the logger using $this->logger, which is not a static way to access it. Since it's a static variable, you got to use self:: just like you did got getLogger, so:
private function __construct()
{
// initialize logger
$writer = new Zend_Log_Writer_Stream(LOG_PATH);
self::$_logger = new Zend_Log($writer);
}