Vanilla PHP, Order status class [INTERNET STORE PROJECT] - php

Question

I need to write an order status class (file Status.php), which will contain certain statuses of an order in my internet store, which I am currently working on.
Desired statuses are:
-Pending (User still haven't confirmed items in the basket).
-Confirmed (User confirmed items in the basket as his order).
-Paid (User has paid for items he bought)
-Complete (Items were sent to user via post office)
It's probably very simple task, but I don't know how to start my work and build this class.
This is my Status.php code so far:
<?php
class Status {
private $id;
private $name;
function __construct() {
$this->id = -1;
$this->name = "";
}
function getId() {
return $this->id;
}
function getName() {
return $this->name;
}
function setName($name) {
$this->name = $name;
}
}
?>
Big thanks to everyone who helps under this post :).

Answer 1

but I don't know how to start my work and build this class.
The code you posted is not a class but some procedural code disguised as OOP. Let's assume I create an object of type Status:
$status = new Status();
Is this an object? What is the value of this new object? It looks like an object but it is just some empty memory. No data, no behaviour, just useless code.
The constructor of a properly implemented class constructs the object, prepares it for usage. When the constructor returns, the object must be fully set; no further $status->setId() and $status->setName() should be required.
This is how I suggest you to define your class:
class Status {
private $id;
private $name;
public function __construct($id, $name) {
// Validate arguments; an object must always be valid
if (! is_int($id) || $id <= 0) {
throw new InvalidArgumentException('$id must be a positive non-zero number.');
}
if (! is_string($name) || empty($name)) {
throw new InvalidArgumentException('$name must be a non-empty string.');
}
// The arguments are valid; go ahead and construct the object
$this->id = $id;
$this->name = $name;
}
}
Now let's create some Status objects:
$pending = new Status(1, 'pending');
$confirmed = new Confirmed(2, 'confirmed');
Depending on how you plan to use the properties of the objects, you will probably not pass the ID as argument to the constructor but generate it internally or use a fixed list of values.
Or you can go one step further, declare the properties and the constructor of class Status as protected and create one child class for each possible value of $status:
class Status {
protected $id;
protected $name;
protected function __construct($id, $name) {
// ...
}
// ...
}
class Pending extends Status {
public function __construct() {
parent::__construct(1, 'pending');
}
}
class Confirmed extends Status {
public function __construct() {
parent::__construct(2, 'confirmed');
}
}
class Paid extends Status {
public function __construct() {
parent::__construct(3, 'paid');
}
}
The properties are protected to allow the methods of the children classes access them (when they are private only the methods of class Status see them). The constructor is protected to prevent the creation of objects of type Status but allow the methods of the children classes (their constructors actually) invoke it. Always call the constructor of the parent class in the constructor of the child class.
This way, when you need to create an object that represents a status, all you have to do is:
$pending = new Pending();
$confirmed = new Confirmed();
// a.s.o.
Don't rush to add the "getters" (the methods that access the object properties and provides the to the client code) you defined in your code. Think what do you want to do with the values stored in a Status object and check if that code can stay in the Status class too. Put code specific to the "pending" status (f.e.) into the Pending class, not into the Status class.
If Status::$name is used only for display then you better implement __toString() instead of getName():
class Status {
// ...
public function __toString()
{
// It is vital here to enforce the type of $this->name into the constructor
// __toString() must return a string
return $this->name;
}
}
This way your code will look nice:
$pending = new Pending();
echo('The status is: '.$pending);
// Output:
// The status is: pending