PHP Readonly Properties?

Question

In using PHP\'s DOM classes (DOMNode, DOMEElement, etc) I have noticed that they possess truly readonly properties. For example, I can read the $nodeName property of a DOMNo

Answer 1

For those looking for a way of exposing your private/protected properties for serialization, if you choose to use a getter method to make them readonly, here is a way of doing this (@Matt: for json as an example):

interface json_serialize {
    public function json_encode( $asJson = true );
    public function json_decode( $value );
}

class test implements json_serialize {
    public $obj = null;
    protected $num = 123;
    protected $string = 'string';
    protected $vars = array( 'array', 'array' );
    // getter
    public function __get( $name ) {
        return( $this->$name );
    }
    // json_decode
    public function json_encode( $asJson = true ) {
        $result = array();
        foreach( $this as $key => $value )
            if( is_object( $value ) ) {
                if( $value instanceof json_serialize )
                    $result[$key] = $value->json_encode( false );
                else
                    trigger_error( 'Object not encoded: ' . get_class( $this ).'::'.$key, E_USER_WARNING );
            } else
                $result[$key] = $value;
        return( $asJson ? json_encode( $result ) : $result );
    }
    // json_encode
    public function json_decode( $value ) {
        $json = json_decode( $value, true );
        foreach( $json as $key => $value ) {
            // recursively loop through each variable reset them
        }
    }
}
$test = new test();
$test->obj = new test();
echo $test->string;
echo $test->json_encode();