PHP: get a result from a chaining method from extended classes?

Question

I am trying to get a result from a chaining method from extended classes below,

class Base
{
    protected $id;

    public function setId($input) {

        $this->id = $input;

        return $this;
    }
}

class PageChildren extends Base
{
    public function getID()
    {
        return $this->id;
    }
}


class Page extends Base
{
    public $hasChidren;

    public function __construct()
    {
        $this->hasChidren = new PageChildren();
    }
}

$page = new Page();
var_dump($page->setId(10)->hasChidren->getID());

But I get null instead of 10. What shall I do to get it right?

score 2 · Answer 1 · answered Sep 27 '13 at 09:17

You are getting the ID of hasChidren, which is a new object of type PageChildren whose ID has never been set, you are not accessing the original object of type base to which you set the ID

You create a page object, when you create it one of his attributes contains a PageChildren object. Then you set the ID of your page object. And in the end you are getting the ID from the PageChildren object, not the Page object.

score 1 · Accepted Answer · answered Sep 27 '13 at 09:17

1

$page->hasChidren->setId(10);
var_dump(page->hasChidren->getID();

answered Sep 27 '13 at 09:17

po_taka

1,816
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27

score 1 · Answer 3 · answered Sep 27 '13 at 09:21

1

You are getting NULL since, when you do a

$page = new Page();

your constructor will run first which has the getID() method. The getID() method does not have anything to return and thus you get a NULL

answered Sep 27 '13 at 09:21

Shankar Narayana Damodaran

68,075
43
96
126

PHP: get a result from a chaining method from extended classes?

3 Answers3