OOP design - multiple classes, helper method or procedural code? - php

Question

I'm trying to learn OOP with PHP. I have a website for a magazine and I've created a class called Magazine with some properties. When loading the page a cover image or a specific article should be loaded, the second variant when a user has selected a year and an issue from two select elements. The second select element is dependent on the first - not all years have the same number of issues. So the correct number of options for the second select element should be generated by the PHP code as well (I don't want to use only JavaScript for this).
Here's the basic code:
class Magazine {
public $contents;
public $cover;
public $currentArticle;
public function __construct($year,$issue) {
$this->contents = ...;
...
}
}
$magazine = new Magazine(...);
And now the question: Where should I create the select elements?
1) In a class of its own?
2) In the Magazine class, maybe through a helper method?
3) In the main code where I create instances of the classes?
Method number one (1a) could perhaps look something like this:
class Magazine {
public $contents;
public $cover;
public $currentArticle;
public function __construct($year,$issue) {
$this->contents = ...;
...
}
}
class SelectMagazine {
public $year;
public $issue;
public function __construct($year,$issue) {
$this->year = ...;
...
}
}
$magazine = new Magazine();
$selectMagazine = new SelectMagazine();
Overkill?
Or I could pass the select element through the Magazine class, but that seems rather pointless since they don't really belong there (1b):
class Magazine {
public $contents;
public $cover;
public $currentArticle;
public function __construct($year,$issue) {
$this->contents = ...;
...
$selectMagazine = new SelectMagazine();
$this->year = $selectMagazine->year;
...
}
}
class SelectMagazine {
public $year;
public $issue;
public function __construct($year,$issue) {
$this->year = ...;
...
}
}
$magazine = new Magazine();
Method number two has the same problem as 1b – the select elements aren't really properties of (an instance of) the Magazine (object), if the objects are supposed to mirror the real world.
Method number 3 - underkill?

Answer 1

You might want to do something like that (not sure about the syntax, I don't really know PHP :))
<?
interface SelectHelper {
function getSelect()
{
}
}
class YearsSelectHelper extends SelectHelper {
public function __construct() {
self->magazines = Database::getMagazineList(); // or something
}
public function getSelect()
{
$select = '';
// Construct the select with the years
// You probably want to use private functions to construct
// the select element.
...
return $select;
}
}
class IssuesSelectHelper extends SelectHelper {
public function __construct($year) {
self->year = $year;
// Get the magazine corresponding to that year
}
public function getSelect()
{
// Same thing as in the other class
}
}
In your view, you instanciate the YearsSelectHelper, and then call getSelect to generate the select element. When the user selects a year, you make an AJAX call to an exposed PHP web service that returns your second select, with the year parameter as AJAX data.