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Object Cloning in PHP

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In simple words 'object cloning' can be defined as copying the object property and assigning to a different object. But when we copy an object then it only owns the reference, not the value.

In PHP this is done by two method-

1) By using clone Keyword-
In this, a shallow copy of the object is made. It means the internal object of the objectA is not cloned to the internal object of objectB.


class CloneableClass { private $_internalObject; public function __construct() { // instantiate the internal member $this->_internalObject = new stdClass(); } } $objectA = new CloneableClass(); $objectB = clone $objectA;












2) By using __clone() method-

 if your object holds a reference to another object which it uses and when you replicate the parent object you want to create a new instance of this other object so that the replica has its own separate copy.
In this the magic method __clone() is used to clone internal object or the referenced one. So objectB will be the exact copy of the objectA.


class CloneableClass { private $_internalObject; public function __construct() { // instantiate the internal member $this->_internalObject = new stdClass(); } // on clone, make a deep copy of this object by cloning internal member; public function __clone() { $this->_internalObject = clone $this->_internalObject; } } $objectA = new CloneableClass(); $objectB = clone $objectA;
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