3.4. Mediator¶

1<?php
2
3interface GroupChatMediatorInterface {
4    public function addUserToGroupChat(User $user, GroupChat $groupChat);
5    public function sendMessageToGroupChat(User $user, GroupChat $groupChat, $message);
6}

 1<?php
 2
 3class User
 4{
 5    private string $name;
 6    private $groupChats = [];
 7
 8    public function __construct(string $name)
 9    {
10        $this->name = $name;
11    }
12
13    public function joinGroupChat(GroupChat $groupChat, GroupChatMediatorInterface $mediator): void
14    {
15        // Add user to the group chat via the mediator
16        $mediator->addUserToGroupChat($this, $groupChat);
17        // Add the group chat to the user's list of group chats
18        $this->groupChats[] = $groupChat;
19    }
20
21    public function sendMessageToGroupChat(GroupChat $groupChat, GroupChatMediatorInterface $mediator, $message): void
22    {
23        // Send message to the group chat via the mediator
24        $mediator->sendMessageToGroupChat($this, $groupChat, $message);
25    }
26
27    public function receiveMessage($message): void
28    {
29        // Print out the received message
30        echo "{$this->name} received message: {$message}\n";
31    }
32}

 1<?php
 2
 3class GroupChat
 4{
 5    private string $name;
 6    private array $users = [];
 7
 8    public function __construct($name)
 9    {
10        $this->name = $name;
11    }
12
13    public function addUser(User $user): void
14    {
15        // Add user to the group chat
16        $this->users[] = $user;
17    }
18
19    public function sendMessage(User $user, $message): void
20    {
21        // Send message to all users in the group chat
22        foreach ($this->users as $u) {
23            if ($u !== $user) {
24                $u->receiveMessage($message);
25            }
26        }
27    }
28}

 1<?php
 2
 3class GroupChatMediator implements GroupChatMediatorInterface
 4{
 5    public function addUserToGroupChat(User $user, GroupChat $groupChat)
 6    {
 7        // Add user to the group chat
 8        $groupChat->addUser($user);
 9    }
10
11    public function sendMessageToGroupChat(User $user, GroupChat $groupChat, $message)
12    {
13        // Send message to the group chat
14        $groupChat->sendMessage($user, $message);
15    }
16}

 1<?php
 2
 3// Create a new mediator
 4$mediator = new GroupChatMediator();
 5
 6// Create some group chats
 7$groupChat1 = new GroupChat("Group Chat 1");
 8$groupChat2 = new GroupChat("Group Chat 2");
 9
10// Create some users
11$user1 = new User("Saleh");
12$user2 = new User("Mina");
13$user3 = new User("Ahmad");
14
15// Add users to group chats
16$user1->joinGroupChat($groupChat1, $mediator);
17$user2->joinGroupChat($groupChat1, $mediator);
18$user2->joinGroupChat($groupChat2, $mediator);
19$user3->joinGroupChat($groupChat2, $mediator);
20
21// Send messages within group chats
22$user1->sendMessageToGroupChat($groupChat1, $mediator, "Hello everyone in Group Chat 1!");
23$user2->sendMessageToGroupChat($groupChat2, $mediator, "Hi all in Group Chat 2!");
24
25// Output:
26// Mina received message: Hello everyone in Group Chat 1!
27// Ahmad received message: Hi all in Group Chat 2!