Decorator Pattern with method relation - php

Question

I use the design pattern Decorator in PHP, and I've got a structure problem.
Here's a simple example to illustrate my problem :
interface MyInterface {
function showUsers($array);
function showUser($i);
}
class MyCLass implements MyInterface {
function showUsers($array)
{
foreach($array as $toto) {
$this->showUser($toto);
}
}
function showUser($i)
{
echo $i;
}
}
class MyCLassDecorator implements MyInterface {
private $inner;
public function __construct(MyInterface $inner)
{
$this->inner = $inner;
}
function showUsers($array)
{
$this->inner->showUsers($array);
}
function showUser($i)
{
echo "User: $i";
}
}
class MyCLassDecorator2 implements MyInterface {
private $inner;
public function __construct(MyInterface $inner)
{
$this->inner = $inner;
}
function showUsers($array)
{
$this->inner->showUsers($array);
}
function showUser($i)
{
$this->inner->showUser($i);
echo " is wonderful";
}
}
$myClass = new MyCLassDecorator2(new MyCLassDecorator(new MyCLass()));
$myClass->showUsers(["Alfred", "Bob", "Claire"]);
With this code, the methods showUser of MyClassDecorator & MyClassDecorator2 will never be called.
What can I do?
Is it forbidden to call another method of the same class? (Not really convenient to split my code)
Is there another way to do this?
Should I create one interface by method ?
Thanks a lot :)
EDIT:
Here is the solution that I finally used, although I'm not really satisfied of it...
I split my code not in methods but in interfaces(services)
Here it is :
interface IShowUsers {
function showUsers($array);
}
interface IShowUser {
function showUser($user);
}
class Services {
static $showUsers;
static $showUser;
}
class MyShowUsers implements IShowUsers {
function showUsers($array)
{
foreach($array as $toto) {
Services::$showUser->showUser($toto);
}
}
}
class MyShowUser implements IShowUser {
function showUser($user)
{
echo $user;
}
}
class MyShowUserDecorator implements IShowUser {
private $inner;
public function __construct(IShowUser $inner)
{
$this->inner = $inner;
}
function showUser($user)
{
echo "User: ";
$this->inner->showUser($user)
}
}
class MyShowUserDecorator2 implements IShowUser {
private $inner;
public function __construct(MyInterface $inner)
{
$this->inner = $inner;
}
function showUser($user)
{
$this->inner->showUser($user);
echo " is wonderful";
}
}
$myClass = new MyShowUserDecorator2(new MyShowUserDecorator(new MyShowUser()));
Services::$showUsers = new MyShosUsers();
Services::$showUser = new MyShowUserDecorator2(new MyShowUserDecorator(new MyShowUser()));
Services::$showUsers->showUsers(["Alfred", "Bob", "Claire"]);
If you have a better solution, I will be happy to know it :)
Of course, I use the decorator pattern to use these decorators in different ways in many projects like in these exemples:
//no decorators
Services::$showUser = new MyShowUser();
//only the first
Services::$showUser = new MyShowUserDecorator(new MyShowUser());
//only the second
Services::$showUser = new MyShowUserDecorator2(new MyShowUser());
So the extend not seems to be a good solution.
Thanks a lot again for giving the right way to do this :)

Answer 1

It seems to me you need to re-think this a bit. If you can provide a clear picture of what you're trying to accomplish then we can provide more insight. But to answer your question directly you can extend the class and then override the method.
http://sandbox.onlinephpfunctions.com/code/61c33b0ce98631986134bf78efcd0391f9b9ab67
<?php
interface MyInterface {
function showUsers($array);
function showUser($i);
}
class MyCLass implements MyInterface {
function showUsers($array = ["Alfred", "Bob", "Claire"])
{
foreach($array as $toto) {
$this->showUser($toto);
}
}
function showUser($i)
{
echo $i;
}
}
// Extend the class in order to override the methods.
class MyCLassDecorator extends MyCLass {
// Also, try removing this method to see what it does.
function showUsers($array = [1,2,3])
{
foreach($array as $toto) {
$this->showUser($toto);
}
}
function showUser($i)
{
echo "c'est la fete chez $i";
}
}
$myClass = new MyCLassDecorator();
$myClass->showUsers();
EDIT
Not sure if I'm being clear or not but the issue is you're expecting inheritance behaviour without using inheritance. How is MyCLass supposed to know about MyCLassDecorator::showUser?
foreach($array as $toto) {
// The issue is this line. You're mixing `decorator` and `inheritance`.
// You should re-think your design. This will not work.
$this->showUser($toto);
}