class property loses value

access9

Hello all-

I have a page that, depending on what stage in the program the user is, loads various screens. So take the following code as an example:

here's our class:

class A
{
    var $a;

function setVar($setToThis)
{
    echo "setting property";
    $this->a = $setToThis;
}

function getVar()
{
    return $this->a;
}	
}

and the corresponding code:

require_once("A.php");

if (!isset($obj))
    $obj = new A;

if (!isset($_POST['isPosted']))
{   

    $obj->setVar('Property is set');
    echo $obj->getVar() . "<br />\n"; // test to see if property is set

echo<<<myForm
<form action="test.php" method="post">
    <input type="submit" name="isPosted">
</form>
myForm;
}

if (isset($_POST['isPosted']))
{
    $thisTest = $obj->getVar();
    echo "<p>property is: " . $thisTest . "</p>\n"; // only prints 'property is: '!
}

I know that the property is set because I can print out the contents right after I set it. But after the form is submitted $thisTest is now empty even though the object is still initialized and availalble to call. Regardless of how the form is posted, shouldn't the property of my object stay set? What am I missing?

Thanks,
a9

PS. I may be looking at this from too much of a Java perspective and PHP may not work this way- let me know!

ahundiak

Objects are not persistant across script invocations. You will need to store your information in a session variable of some sort.

access9

I knew someone was going to say that! Thanks for the reply. Do you know if this behavior will change with PHP5?

-a9

ahundiak

It will not. Using sessions is quite easy. And you can simply store your objects in a session.

It's really the same thing that Java does with session beans.

Remember that http is a stateless protocol. You always have to do something to share information between scripts.

drew010

no, that wont be added in php5 because its not the nature of a class to persist thru several instances of a script or a session. you could [man]serialize[/man] a class variable and pass it along via a session.

if you do want to see the oo changes in php5, have a look at this page: http://www.php.net/zend-engine-2.php

access9

I use sessions now for a few things, but I hadn't realized that I would need to serialize my objects between script instances. SO I guess the code

if (!isset($obj))
    $obj = new Classname;

isn't nessesary. Hmm, php OO is implemented in a way I hadn't thought of. Thanks again.

-a9