{"id":159,"date":"2018-07-12T10:31:06","date_gmt":"2018-07-12T10:31:06","guid":{"rendered":"http:\/\/itp9.epgpbooks.inflibnet.ac.in\/?post_type=chapter&p=159"},"modified":"2018-12-07T10:52:53","modified_gmt":"2018-12-07T10:52:53","slug":"oop-iii-in-php","status":"publish","type":"chapter","link":"https:\/\/ebooks.inflibnet.ac.in\/itp9\/chapter\/oop-iii-in-php\/","title":{"rendered":"OOP \u2013 III in PHP"},"content":{"raw":"
\"epgp<\/a>\r\n<\/span><\/div>\r\n
\r\n\r\n \r\n\r\n \r\n\r\n \r\n\r\nClone an object:<\/strong>\r\n\r\n \r\n

Working with objects, it may be required to copy an object. To make a copy of an object, the assignment operator (=) is used. The assignments operator just creates a new reference to the same object. In other words, both the variables points to the same object. So, if you change the properties of one object, that will also change the properties of other object too.<\/p>\r\n \r\n\r\nLet us check it by example.\r\n\r\n \r\n\r\n<?php\r\n\r\nclass Employee\r\n\r\n{\r\n\r\nprivate $eid, $ename; \/\/ properties of a class Employee\r\n\r\npublic function __construct($eid,$ename)\r\n\r\n{\r\n\r\n$this->eid = $eid;\r\n\r\n$this->ename = $ename;\r\n\r\n}\r\n\r\n \r\n\r\n\/\/ Getter and setter to set properties of object\r\n\r\n \r\n\r\npublic function geteid() \/\/get method to get employeeid\r\n\r\n{\r\n\r\nreturn $this->eid;\r\n\r\n}\r\n\r\npublic function seteid($value) \/\/set method to set employeeid\r\n\r\n{\r\n\r\n$this->eid = $value;\r\n\r\n}\r\n\r\n<\/div>\r\n

\r\n\r\n\u00a0 \u00a0 \u00a0 \/\/getname\r\n\r\n \r\n\r\npublic function getename()\r\n\r\n{\r\n\r\nreturn $this->ename;\r\n\r\n}\r\n\r\npublic function setename($value)\r\n\r\n{\r\n\r\n$this->ename = $value;\r\n\r\n}\r\n\r\n}\r\n\r\n$obj1 = new Employee(101,'Vipul');\r\n\r\necho '<br> $obj1 is now : ';\r\n\r\nprint_r($obj1);\r\n\r\n$obj2 = new Employee(110,'Dhaval');\r\n\r\necho '<br> $obj2 is now : ';\r\n\r\nprint_r($obj2);\r\n\r\n$obj1 = $obj2;\r\n\r\necho '<br> after assignment operator now object 2 is <br>'; print_r($obj2);\r\n\r\necho '<br> after assignment operator now object 1 is <br>'; print_r($obj1);\r\n\r\necho \"<br> set name of obj2 to vimal <br>\";\r\n\r\n$obj2->setename('Vimal');\r\n\r\necho '<br> $obj2 is after setname is: <br>\u00a0 ';<\/span>\r\n\r\nprint_r($obj2);<\/span>\r\n\r\necho '<br> $obj1 is after obj2 setname is: <br> ';<\/span>\r\n\r\nprint_r($obj1);<\/span>\r\n\r\n?><\/span>\r\n\r\n<\/div>\r\n
\r\n\r\n \r\n\r\nThen the output will be:\r\n\r\n \r\n

$obj1 is now : Employee Object ( [eid:Employee:private] => 101 [ename:Employee:private] => Vipul )<\/p>\r\n

$obj2 is now : Employee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )<\/p>\r\n

after assignment operator now object 2 is<\/p>\r\n

Employee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )<\/p>\r\n

after assignment operator now object 1 is<\/p>\r\n

Employee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )<\/p>\r\n

set name of obj2 to vimal<\/p>\r\n$obj2 is after setname is:\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Vimal )\r\n\r\n$obj1 is after obj2 setname is:\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Vimal )\r\n\r\n<\/div>\r\n \r\n

\r\n\r\n\u00a0 \u00a0 To copy the object, clone keyword is also used.\r\n\r\nThe syntax to clone an object is:\r\n\r\nclone <objectName>;\r\n\r\n \r\n\r\nPHP makes a shallow copy of an object when an object is copied.\r\n\r\n \r\n

Shallow copy means it copies the memory location of an object. Changes in shallow copy is reflected on original object. To not create shallow copy, cloning of an object is required.<\/p>\r\n \r\n\r\nLet us understand the use of clone by example.\r\n\r\n \r\n\r\n<?php\r\n\r\nclass Employee\r\n\r\n{\r\n\r\nprivate $eid, $ename; \/\/ properties of a class Employee<\/span>\r\n\r\npublic function __construct($eid,$ename)<\/span>\r\n\r\n{<\/span>\r\n\r\n$this->eid = $eid;<\/span>\r\n\r\n$this->ename = $ename;<\/span>\r\n\r\n}<\/span>\r\n\r\n\/\/ Getter and setter to set properties of object<\/span>\r\n\r\npublic function geteid()\u00a0 \/\/get method to get employeeid<\/span>\r\n\r\n{<\/span>\r\n\r\nreturn $this->eid;<\/span>\r\n\r\n}<\/span>\r\n\r\npublic function seteid($value) \/\/set method to set employeeid<\/span>\r\n\r\n{<\/span>\r\n\r\n$this->eid = $value;<\/span>\r\n\r\n}<\/span>\r\n\r\n \r\n\r\n\/\/getname<\/span>\r\n\r\n<\/div>\r\n

\r\n\r\n\u00a0 \u00a0public function getename()\r\n\r\n{\r\n\r\nreturn $this->ename;\r\n\r\n}\r\n\r\npublic function setename($value)\r\n\r\n{\r\n\r\n$this->ename = $value;\r\n\r\n}<\/span>\r\n\r\n}<\/span>\r\n\r\n$obj1 = new Employee(101,'Vipul');<\/span>\r\n\r\necho '<br> $obj1 is now : ';<\/span>\r\n\r\nprint_r($obj1);<\/span>\r\n\r\n$obj2 = new Employee(110,'Dhaval');<\/span>\r\n\r\necho '<br> $obj2 is now : ';<\/span>\r\n\r\nprint_r($obj2);<\/span>\r\n\r\n$obj1 = clone $obj2;<\/span>\r\n\r\necho '<br> after cloning now object 2 is <br>';<\/span>\r\n\r\nprint_r($obj2);<\/span>\r\n\r\necho '<br> after cloning now object 1 is <br>';<\/span>\r\n\r\nprint_r($obj1);<\/span>\r\n\r\necho \"<br> set name of obj2 to vimal <br>\";<\/span>\r\n\r\n$obj2->setename('Vimal');<\/span>\r\n\r\necho '<br> $obj2 is after setname is: <br> ';<\/span>\r\n\r\nprint_r($obj2);<\/span>\r\n\r\necho '<br> $obj1 is after obj2 setname is: <br> ';<\/span>\r\n\r\nprint_r($obj1);<\/span>\r\n\r\n$obj2->seteid(111);<\/span>\r\n\r\necho '<br> $obj2 is after seteid is: <br> ';<\/span>\r\n\r\nprint_r($obj2);<\/span>\r\n\r\necho '<br> $obj1 is after obj2 seteid is: <br> ';<\/span>\r\n\r\nprint_r($obj1);<\/span>\r\n\r\n?><\/span>\r\n\r\n<\/div>\r\n
\r\n\r\n \r\n\r\nThe output is:\r\n\r\n \r\n\r\n$obj1 is now : Employee Object ( [eid:Employee:private] => 101 [ename:Employee:private] => Vipul )\r\n\r\n$obj2 is now : Employee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )\r\n\r\nafter cloning now object 2 is\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )\r\n\r\nafter cloning now object 1 is\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )\r\n\r\nset name of obj2 to vimal\r\n\r\n \r\n\r\n$obj2 is after setname is:\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Vimal )\r\n\r\n$obj1 is after obj2 setname is:\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )\r\n\r\n$obj2 is after seteid is:\r\n\r\nEmployee Object ( [eid:Employee:private] => 111 [ename:Employee:private] => Vimal )\r\n\r\n$obj1 is after obj2 seteid is:\r\n\r\nEmployee Object ( [eid:Employee:private] => 110 [ename:Employee:private] => Dhaval )\r\n\r\n<\/div>\r\n
\r\n\r\n \r\n\r\nInspecting an object<\/strong>\r\n