Initializing class properties - php

Question

I need to initialize some properties in my class. I don't use constructor, only set methods.
<?php
namespace Task;
class Log {
private $_views = null;
private $_urls = null;
private $_traffic = null;
/**
* #param int $count
*/
public function setViewCount(int $count) {
$this->$_views = $count;
}
/**
* #return int
*/
public function getViewCount() {
return $this->$_views;
}
/**
* #param int $count
*/
public function setUrlCount(int $count) {
$this->$_urls = $count;
}
/**
* #return int
*/
public function getUrlCount() {
return $this->$_urls;
}
/**
* #param int $trafficData
*/
public function setTraffic(int $trafficData) {
$this->$_traffic = $trafficData;
}
/**
* #return int
*/
public function getTraffic() {
return $this->$_traffic;
}
}
?>
Then I try to set values to properties and save it to associative array.
<?php
require 'Log.php';
use Task;
$log = new Task\Log();
$log->setViewCount(44);
$log->setUrlCount(55);
$log->setTraffic(99999);
$res = array("views" => $log->getViewCount(), "urls" => $log->getUrlCount(), "traffic" => $log->getTraffic());
echo json_encode($res);
?>
After encoding to json I see that any element of array has last value I set to object. In this example last is 99999 for Traffic so I got {"views":99999,"urls":99999,"traffic":99999}. What's the reason of such behaviour and how can I get correct values in each element of array?

Answer 1

$this->$_views this accesses not the field named _views but a field with the name stored in variable $_views.
Since you have no such variable the name assumed empty, thus the same name for each of setters or getters.
In short: you need to remove $ after ->:
$this->_urls = $count;
etc.