PHP Language - Problem with object cloning in PHP5

Author

Problem with object cloning in PHP5

AmicoFritz

2006-05-12, 6:58 pm

When I clone an istance of System class I want to clone all SubSystem
istances in $subsystems array too, so I tryed with this code:

class System {
public $name;
public $subsystems = array();

function __construct($name){
$this->name = $name;
}

function __clone(){
foreach( $this->subsystems as $key => $item ){
$this->subsystems[$key] = clone($this->subsystems[$key]);
}
}
}

class SubSystem {
public $name;
public $type = 2;
public $skip_AP_search = false;

function __construct($name){
$this->name = $name;
}
}

But when I clone...

--- var_dump($orig->subsystems);

array(1) {
[0]=>
&object(SubSystem)#12 (7) {
["name"]=>
string(4) "sub1"
["type"]=>
int(2)
["skip_AP_search"]=>
bool(false)
}
}

--- var_dump($copy->subsystems);

array(1) {
[0]=>
&object(SubSystem)#12 (7) {
["name"]=>
string(4) "sub1"
["type"]=>
int(2)
["skip_AP_search"]=>
bool(false)
}
}

So the istances in the arrays are the same :(

What's wrong?

Colin McKinnon

2006-05-12, 6:58 pm

AmicoFritz wrote:

> When I clone an istance of System class I want to clone all SubSystem
> istances in $subsystems array too, so I tryed with this code:

<snip>
>
> function __clone(){
> foreach( $this->subsystems as $key => $item ){
> $this->subsystems[$key] = clone($this->subsystems[$key]);
> }
> }

because you've replaced the thing refered to by '$this->subsystems[$key]'
with a clone of '$this->subsystems[$key]' - and that thing is currently
referenced by the arrays of both objects.

Off the top of my head, I'd try:

function __clone()
{
$new=array();
foreach( $this->subsystems as $key => $item ){
$new[$key]=clone($this->subsystems[$key]);
}
$this->subsystems=$new;
}

Or for an ugly fix, instead of $newObj = clone $oldObj,

$newObj=unserialize(serialize($oldObj));

HTH

C.

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