5

I have a custom class object in PHP named product:

final class product
{   
    public $id;
    public $Name;
    public $ProductType;
    public $Category;
    public $Description;
    public $ProductCode;
}

When passing an object of this class to my Data Access Layer I need to cast the object passed into a type of the product class so I can speak to the properties within that function. Since type casting in PHP works only with basic types what is the best solution to cast that passed object?

final class productDAL
{
    public function GetItem($id)
    {
        $mySqlConnection = mysql_connect('localhost', 'username', 'password');
        if (!$mySqlConnection) { trigger_error('Cannot connect to MySql Server!'); return; }
        mysql_select_db('databaseName');
        $rs = mysql_query("SELECT * FROM tblproduct WHERE ID='$id';");
        $returnObject = mysql_fetch_object($rs, 'product');
        return $returnObject;
    }

    public function SaveItem($objectToSave, $newProduct = false)
    {
        $productObject = new product();
        $productObject = $objectToSave;

        echo($objectToSave->Name);
        $objectToSave->ID;

    }
}

Right now I am creating a new object cast as a type of product and then setting it equal to the object passed to the function. Is there a better way of accomplishing this task? Am I going about the wrong way?

EDITED FOR CLARITY - ADD FULL PRODCUTDAL CLASS

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2
  • possible duplicate of Convert/cast an stdClass object to another class Commented Feb 8, 2011 at 15:35
  • Oh, maybe what you are aiming for are interfaces? You can then type-hint this interface in your function signature, and as such be sure that all object contracted to have these properties (even if the interface is empty). Commented Feb 8, 2011 at 15:52

4 Answers 4

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9

You don't need to cast the object, you can just use it as if it was a product.

$name = $objectToSave->Name;
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3 Comments

Hmm... you seem to be correct. Intellisense in NetBeans will not work due to it not being cast properly but it seems this is a real solution. Any pitfalls to operating this way?
Oh, a great way to trick Intellisense : if (false) $objectToSave = new product; . Speeds up development and can be removed afterwards.
I upvoted this answer. But with this answer, no IDE will know that $objectToSave is a Product, having a Name property. Hence, the IDE does not help you. Tricking the IDE with non-production code to get helpful intellisense should be unnecessary. True casting would allow the IDE know the type, and provide better intellisense/autocomplete.
1

I´m not sure what you are trying to achieve, but if $objectToSave is already of class product:

  • You can simply call $objectToSave->SaveItem() (assuming SaveItem() is part of the product class) and access it´s properties in the function like $this->Name, etc.;
  • In your code $productObject and $objectToSave will hold a reference to the same object.
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Comments

1

Type casts in PHP are done like this:

$converted = (type) $from;

Note, that this won't work if the object types are not compatible (if for example $form happens to be a string or object of mismatching type).

But usual solution (called Active Record pattern, present for example in Zend Framework) is to have a base class for a database item called Row. Individual items (for example the class product from your sample) then inherit from this class.

Typical ZF scenario:

$table = new Product_Table();
$product = $table->find($productId); // load the product with $productId from DB
$product->someProperty = $newPropertyValue;
$product->Save(); // UPDATE the database

Which is IMO much better than your solution.

EDIT:

You can't cast between two unrelated objects, it is not possible.

If you want to use the DAL like this, skip the "product" object and go for simple associative array. You can enumerate over its members with foreach, unlike object's properties (you could use reflection, but that's overkill).

My recommendation: Go for the Active Record pattern (it is easy to implement with magic methods). It will save you a lot of trouble.

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8 Comments

I've tried this method but it generates an error and renders the page useless. ($productObject = (product)$objectToSave;) I have an error capturing system setup to report errors back but it doesn't allow the page to even load that far. If I'm not mistaken, that type of casting can only be done with certain object, correct? php.net/manual/en/language.types.type-juggling.php
What is the type of $objectToSave?
IMO, type-casting cannot be used for reference-type variables. So even if you cast a product into a row, it still behaves like a product and still has the type "object reference".
The type of $objectToSave is the product class I've created. In addition, I'm not using ZF for now.
So is the product class in the first sample same as the one created in the second sample?
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0

Currently, you are creating a new Product, then discarding it immediately (as its reference is replaced by $objectToSave.) You will need to copy its properties one by one, I regret.

foreach (get_object_vars($objectToSave) as $key => $value)
{
    $product->$key = $value;
}

(If the properties of $objectToSave are private, you will need to a expose a method to_array() that calls get_object_vars($this).)

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2 Comments

You can just clone the object if you want a real copy, but that´s completely unnecessary just to save it in a database...
clone wouldn't change the class attached to the properties.

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