You can do it like this:
class Example {
private $__readOnly = 'hello world';
function __get($name) {
if($name === 'readOnly')
return $this->__readOnly;
user_error("Invalid property: " . __CLASS__ . "->$name");
}
function __set($name, $value) {
user_error("Can't set property: " . __CLASS__ . "->$name");
}
}
Only use this when you really need it – it is slower than normal property access. For PHP, it’s best to adopt a policy of only using setter methods to change a property from the outside.