Using instanceof to check and modify input - php

Question

I am using instanceof to check class instances and want to modify input data if class already has instance with same data. below example demonstrates my problem in detail where i have two unique array inputs and third one is duplicate array of second where instanceof supposed to work and modify input.
/**
* Foo Class
*/
class Foo {
public $bar = array();
public function __construct() {}
public function add( $bar ) {
if ( $bar['ID'] instanceof Baz ) { // inctanceof not working as i am expecting. supposed to modify duplicate occurrence
//if bar['ID'] is already instance of Baz then we are trying to modify bar ID before pass it so Baz.
$bar['ID'] = $bar['ID'] . rand();
$this->bar[ $bar['ID'] ] = new Baz( $bar );
}
else {
$this->bar[ $bar['ID'] ] = new Baz( $bar );
}
}
}
Class Baz
/**
* Class Baz
*/
class Baz {
public $ID;
public function __construct( $bar ) {
$this->ID = $bar['ID'];
}
}
Instance
$foo = new Foo();
$bar = array( 'ID' => 'bar1' );
$foo->add( $bar );
$bar2 = array( 'ID' => 'bar2' );
$foo->add( $bar2 );
$bar3 = array( 'ID' => 'bar2' ); //duplicate ID
$foo->add( $bar3 );
Print
print_r( $foo );
Output
Foo Object
(
[bar] => Array
(
[bar1] => Baz Object
(
[ID] => bar1
)
[bar2] => Baz Object
(
[ID] => bar2
)
)
)
Expected Output
Foo Object
(
[bar] => Array
(
[bar1] => Baz Object
(
[ID] => bar1
)
[bar2] => Baz Object
(
[ID] => bar2
)
[bar2{random number}] => Baz Object
(
[ID] => bar2{random number}
)
)
)
what i am doing wrong in here? kindly guide me and alternate solution is also applicable.

Answer 1

You Foo class should look like:
class Foo {
public $bar = array();
public function __construct() {}
public function add( $bar ) {
if (isset($this->bar[ $bar['ID'] ]) && $this->bar[ $bar['ID'] ] instanceof Baz ) { // inctanceof not working as i am expecting. supposed to modify duplicate occurrence
//if bar['ID'] is already instance of Baz then we are trying to modify bar ID before pass it so Baz.
$bar['ID'] = $bar['ID'] . rand();
$this->bar[$bar['ID']]= new Baz( $bar );
}
else {
$this->bar[ $bar['ID'] ] = new Baz( $bar );
}
}
}