php - reset/clear an object? - php

Question

What I'm trying to do is use a temporary object to store values and then reset it back to empty without having to uset($tmpObject); ?
Here is some example code:
class Object {
function ResetObject(){
// code to remove all variables in an object here?
}
}
$tmpObject = new Object();
foreach ($myArray as $arr){
$tmpObject->val1 = "string1";
$tmpObject->val2 = "string2";
$tmpObject->val3 = "string3";
$tmpObject->val4 = "string4";
$template->set('tmpObject',$tmpObject);
$tmpObject->ResetObject();
}
Anyone have any ideas?

Answer 1

class Object {
function ResetObject() {
foreach ($this as $key => $value) {
unset($this->$key);
}
}
}
See: Object iteration

Answer 2

The accepted answer has a minor flaw which is that unsetting a property actually completely removes it from that object, so that a check like $this->someProperty == null would trigger an "Undefined property" notice. Properties are null by default, so this would be more correct:
class Object {
function resetObject() {
foreach ($this as $key => $value) {
$this->$key = null; //set to null instead of unsetting
}
}
}
There's also the possibility that some of the properties could have been given default values (e.g. protected $someArray = array();)...if you want to reset all the properties back to their original default values then you have to use reflection:
class Object {
function resetObject() {
$blankInstance = new static; //requires PHP 5.3+ for older versions you could do $blankInstance = new get_class($this);
$reflBlankInstance = new \ReflectionClass($blankInstance);
foreach ($reflBlankInstance->getProperties() as $prop) {
$prop->setAccessible(true);
$this->{$prop->name} = $prop->getValue($blankInstance);
}
}
}
That may be overkill but could be important in some scenarios. Note that this would fail if the class had required constructor arguments; in that case you could use ReflectionClass::newInstanceWithoutConstructor (introduced in PHP 5.4), then call __construct() manually after calling resetObject().

Answer 3

If your class has a constructor method which initialises everything, then you could just call that again to reset.

Answer 4

<?php
function reset() {
foreach (get_class_vars(get_class($this)) as $var => $def_val){
$this->$var= $def_val;
}
}
?>

Answer 5

Instead of unset and even setting null, setting to default may be a better idea
class Foo {
public $bar = 'default bar';
private $baz = 'something';
function __construct ()
{
/* assign whatever */
}
public function resetMe():Foo
{
$instance = new Foo();
foreach($instance as $k => $v)
$this->{$k} = $v;
}
return $this;
}
To use this
$foo = new Foo();
$foo->bar = 'set something different';
echo $foo->bar; // 'set something different'
$foo->resetMe();
echo $foo->bar; // 'default bar'

Answer 6

Reinitializing the variable will restore all object members to their preset values.
<?php
class Object {
public $val1 = "val1";
public $val2 = "val2";
}
$tmpObject = new Object();
$tmpObject->val1 = "string1";
$tmpObject->val2 = "string2";
$tmpObject->val3 = "string3";
$tmpObject->val4 = "string4";
var_dump($tmpObject);
$tmpObject = new Object();
var_dump($tmpObject);
?>
Outputs:
object(Object)#1 (4) {
["val1"]=>
string(7) "string1"
["val2"]=>
string(7) "string2"
["val3"]=>
string(7) "string3"
["val4"]=>
string(7) "string4"
}
object(Object)#2 (2) {
["val1"]=>
string(4) "val1"
["val2"]=>
string(4) "val2"
}

Answer 7

Another way which combine unset and set with default value.
class Object {
public function resetObject()
{
$clean = new self;
foreach ($this as $key => $val){
// If the attribute have a default value, use it
if (isset($clean->$key)){
$this->$key = $clean->$key;
}else{
unset($this->$key);
}
}
}
}

Answer 8

You can do this with reflection:
private function resetPropertiesToDefault()
{
$blankInstance = $this->newInstance();
$reflBlankInstance = new \ReflectionClass($blankInstance);
foreach ($reflBlankInstance->getProperties() as $prop) {
if ($prop->isStatic()) {
continue;
}
$prop->setAccessible(true);
$this->{$prop->name} = $prop->getValue($blankInstance);
}
}