How to solve the code duplication problem?

Question

In Wordpress I am creating a custom screen in the administration area.

That’s why I’m extending my class customProductsListTable the class WP_List_Table:

class customProductsListTable extends WP_List_Table

I have another class for another custom screen that extends the same class WP_List_Table:

class customReviewsListTable extends WP_List_Table

The problem is that in the classes customProductsListTable and customReviewsListTable created some methods that are common and that do not exist in the class WP_List_Table.

So we have the following scenario:

• The classes customReviewsListTable and customProductsListTable do overwrite of some class methods WP_List_Table, but the code behaves differently in each class.

• The classes customReviewsListTable and customProductsListTable have new methods but with the same behavior.

Clearly I am duplicating code in both classes, but we cannot in PHP inherit more than one class.

How to solve the code duplication problem?

Answer 1

Create an intermediate class, something like that:

class CustomListTable extends WP_List_Table

In it overwrite the methods you want and create new ones that will be common. Then inherit like this:

class CustomProductsListTable extends CustomListTable

class CustomReviewsListTable extends CustomListTable

I put in the Github for future reference.

In these classes you can overwrite and create new methods that are specific to them.

I kept your nomenclature, but note that it diverges from the one used in Wordpress. This is confusing. Although it is confusing for all of PHP.

I have the impression that this intermediate class may be abstract, but without seeing the whole context.