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Reference an array index, not the value it stores?

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Oct 03.2009

So I have an MVC-style framework I’m working on, and I would like to give it the following functionality:

Any number of instances of a model with a certain ID can be created at once, but as soon as a save() method is called on one of these instances, all references to other models with the same ID will now point to the saved one.

The problem comes when I try to track all the references to the different instances of the same model. What I would like to do is store all of the instances in an array, then instead of returning references to the objects themselves when they are pulled, I would return references to the positions in the array. That way, when I save, I can simply go through the array and set each entry to a reference to the saved instance.

As far as I know, however, this is not possible with PHP. Is there any other alternative or perhaps a pattern that is used for cases like this?

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3 Comments(s) ↴

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@Four_StaplesauthorOct 03.2009 — This might help to better illustrate what I want to do:[code=php]<?php
class A {
public static $instances = array();
public $variable = 'original value';

public static function get() {
return self::$instances[] = new A();
}

public function save() {
// needs to set all references to A objects to $this
}
}

$a1 = A::get();
$a2 = A::get();
$a3 = A::get();

$a1->variable = 'updated value';
$a1->save();

echo $a2->variable; // I want this to now be a reference to $a1->variable (ie. output 'updated value')[/code]
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@NogDogOct 03.2009 — Would it make sense to make [b]$variable[/b] static?
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@Four_StaplesauthorOct 04.2009 — Would it make sense to make [b]$variable[/b] static?[/QUOTE]

Unfortunately no, I would like each instance of A to be able to have its own property values, but when one of them is saved ($a1->save()) all other instances of it would take on the saved values ($a2 and $a3 would have the saved values as well).

When I posted the question I hadn't slept in a good 24 hours, so I didn't think of the following solution:[code=php]<?php
class A {
public static $instances = array();
public $variable = 'original value';

public static function get() {
return self::$instances[] = new A();
}

public function save() {
// <do some stuff to update DB>
$this->sync();
}

public function sync() {
foreach(self::$instances as $instance) {
if($instance !== $this) {
$instance->variable = $this->variable;
}
}
}
}

$a1 = A::get();
$a2 = A::get();
$a3 = A::get();

$a1->variable = 'updated value';
$a1->save();

echo $a2->variable;[/code]So nevermind! ?
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