如何在我的类中使用PHP的__get（）和__set（）来定义字段？

Question

I've had a good read of the PHP specs on overloading, and most of the examples appear to be intended to simply allow defining of custom fields (similar to stdClass).

But what about the private fields defined in my class? How should these be retrieved/assigned? I could do a switch on possible values and act on certain values:

class A
{
    private $name;
    private $age;

    public function __get( $var )
    {
        switch ( $var )
        {
            case 'name':
                return $this->name;
                break;
            case 'age':
                return $this->age+10; // just to do something different ;)
                break;
            default:
                break;
        }
    }
}

Is this the best method, or is there another generally accepted best practice? (I don't know if it's possible to loop class variables inside a class, but regardless that's not appropriate in most situations since you don't want to return everything.)

Answer 1

This would effectively make them public, and usually this gains you nothing over simply using public properties (but you pay performance penalty and have to write more code, risk bugs).

Use that only if you have existing code that uses public property and you suddenly need getter/setter for it (like your example with age).

If you need to execute some code when property is read/written (e.g. make it read-only or lazily fetch from the database), then you should use normal getters/setters (getAge()/setAge()).