PHP - how to tell the object whos its creator? - php

Question

HI!
basicly what I ask u to tell me is how to put a "parent" reference into the object
I need it to make example of "extracting method with method object" - one of mostly used refactoring in Java or C#
in Java refering to "parent object" looks like this:
class someClass {
MyObject myObj = new MyObject(this);
}
and thats it :)
but I dont know, how to do the same in PHP
maybe if its imposible you would tell me how you extract your methods out of your classes to new class, that has to do what that method did.
so in other words...
1 - I have class with big and hard to read / refactor method.
2 - I extract that method to new class, giving it fields in place of parameters and method like "execute" - to proced all that this class has to do for me.
3 - I put object of my class to my old function class and I call its method "execute" - so the all logic that was in my_big_method is done.

Answer 1

The best method is inheritance, where you call the parent keyword to access the parent class like so:
class Child extends Father
{
public function __construct()
{
parent::__construct();
}
}
class Father
{
public function __construct()
{
echo "Father says hello";
}
}
new Child();
using the parent keyowrd you can call the constructor like so parent::__construct()
Example: http://codepad.org/kW6dfVMs
if your looking at Injection then you could do something like this.
class Master
{
private $Slave;
public function __construct(Slave $Slave)
{
$this->Slave = $Slave;
}
}
$Master = new Master(new Slave);
if your unsure of the object that should be passed in but you know that it should have a certain interface / set of methods you can get a little more complex and do something like so:
class Master
{
private $Slave;
public function __construct(ISlave $Slave)
{
$this->Slave = $Slave;
}
}
interface ISlave
{
//Declaration of methods
}
class SomeSlaveObject implements ISlave{}
$Master = new Master(new SomeSlaveObject);

Answer 2

Have you tried using the $this keyword?

Answer 3

Easiest way is to pass a reference to the parent object in the constructor, though I may be misunderstanding your goal.
class myClass {
private $parent = false;
function __construct ($parent=false) {
$this->parent = $parent;
}
}
If you are extending a base class, you can use the parent operator:
class otherClass {
function someMethod() {
return 1;
}
}
class myClass extends otherClass {
function aMethod() {
// parent keyword here would refer to "otherClass"
return $this->someMethod();
}
}
Check out the doc on parent: http://php.net/manual/en/keyword.parent.php

Answer 4

PHP version of your example:
class someClass {
public function createObject() {
$myObj = new MyObject($this);
}
}
not much different than java, just less types and more $ signs.
"parent" is a keyword in php, like the java "super" so your question is a little confusing.

Answer 5

I tried with "$this", but "php guy" in my company told me that I cant use $this that is not refering to field or function of current class (that it cant refer to whole class)
my code looks like this:
class to refactor:
class AccountBeforeRefactoring {
// (...)
public function makeTransfer($amount, $destinationAccount){
$transferFee = 1;
if ($amount > 1000){
$transferFee = 1 + $amount * 0.0001;
}
$this->connectToElixir();
// (...)
// (...)
// (...)
$this->debit($amount + $transferFee);
}
}
and it becomes:
class extracted - that was my method:
class TransferMaker {
private $account;
private $amount;
private $destinationAccount;
private $transferFee;
public function __construct($source, $amount, $destinationAccount){
$this->account = $source;
$this->amount = $amount;
$this->destinationAccount = $destinationAccount;
$this->transferFee = 1;
}
public function make(){
if ($this->amount > 1000){
$this->transferFee = 1 + $this->amount * 0.0001;
}
$this->account->connectToElixir();
// (...)
// (...)
// (...)
$this->account->debit($this->amount + $this->transferFee);
}
}
is constructor there made in right way?
and now I need, to make object of MakeTransfer inside my Account class - I tried it this way - is it ok?
class Account {
// (...)
public function makeTransfer($amount, $destinationAccount){
new TransferMaker($this, $amount,
$destinationAccount).make();
}
}
and again - can I just this "$this" just like this? ;)
will my code work? it does compile in Eclipse, but that can mean none.