what does Threshold means in php code

Question

Can someone help me what does "Threshold" means in PHP code. The code goes like this hereunder:

function IsRequestLocked($request_date, $status=0){

   $retval = true;

   if($status==0){

    $current_date = mktime(23, 59, 59, intval(date("n")),
        intval(date("j")), intval(date("Y"))); 

    if($this->Threshold['THRESHOLD_TYPE']){ 
        $request_date = mktime(23, 59, 59, 
        intval(date("n", $request_date)), 
        intval(date("j",$request_date)) + intval($this->Threshold['THRESHOLD']), 
        intval(date("Y",$request_date))); 
     }else{
        $request_date = mktime(23, 59, 59, 
        intval(date("n", $request_date)), 
        intval(date("j",$request_date)) - intval($this->Threshold['THRESHOLD']), 
        intval(date("Y",$request_date))); 
     }
   $retval = ($current_date > $request_date);       
   }
   return $retval;
}

Answer 1

A threshold in PHP means the same as it does in English: a limit beyond which something changes.

Classical sense, the threshold of your water tank is where the overflow tube is. If the water gets to that level, it will flow out of the tank rather than continuing to fill it.

Computer-related: the threshold of your server room is about 30 degrees Celsius. Beyond that, alarms should start going 'Whoop Whoop' and someone had better check out the aircon.

Or, if the requests to a web server farm start banking up, another instance of the server is bought online to hopefully help out (capacity on demand).

In your particular case, the code is simply adding or subtracting a threshold depending on its type and comparing it to the current date. Beyond that, I can't give much more since I have no further information about your application.

---

Based on the names of functions and variables, my best bet would be that requests can either be locked for a certain time before their request date or a certain time after. An example of the former may be an appointment with a customer. Once it gets within (e.g.) two days, you're not allowed to change the date of the appointment, lest you invoke the wrath of said customer.

For the latter, maybe once a request to change a password has been enacted, the request must stay around for five days (but be non-editable) to ensure the user doesn't change the pasword to often.

Fairly contrived examples, I'll admit, but since I know little of your application, it's the best I could do.