Mediator Pattern Generator

Overview

Generates Mediator pattern components for PHP 8.4 to coordinate complex interactions between multiple objects without them referencing each other directly.

When to Use

• Complex communication between multiple objects
• Reducing coupling in event-driven systems
• Coordinating UI components or form elements
• Command bus / Query bus implementation
• Chat room / notification hub scenarios
• Workflow coordination

Generated Components

Component	Location	Purpose
MediatorInterface	src/Application/{Context}/Mediator/	Defines mediation contract
ConcreteMediator	src/Application/{Context}/Mediator/	Implements coordination logic
ColleagueInterface	src/Application/{Context}/Mediator/Colleague/	Participant contract
AbstractColleague	src/Application/{Context}/Mediator/Colleague/	Base with mediator access
ConcreteColleagues	src/Application/{Context}/Mediator/Colleague/	Participating components
Tests	tests/{Context}/Application/Mediator/	Unit tests

Input Requirements

1. Name - Mediator name (e.g., "OrderWorkflow", "ChatRoom")
2. Context - Bounded context (e.g., "Order", "Notification")
3. Colleagues - List of participating components
4. Events - Events to coordinate (optional)

Template: Mediator Interface

<?php

declare(strict_types=1);

namespace App\{Context}\Application\Mediator;

use App\{Context}\Application\Mediator\Colleague\ColleagueInterface;

interface {Name}Mediator
{
    public function notify(ColleagueInterface $sender, string $event, mixed $data = null): void;
    public function register(ColleagueInterface $colleague): void;
    public function send(string $request, mixed $data = null): mixed;
}

Template: Colleague Interface

<?php

declare(strict_types=1);

namespace App\{Context}\Application\Mediator\Colleague;

use App\{Context}\Application\Mediator\{Name}Mediator;

interface ColleagueInterface
{
    public function getName(): string;
    public function setMediator({Name}Mediator $mediator): void;
    public function handle(mixed $data): mixed;
}

Template: Abstract Colleague

<?php

declare(strict_types=1);

namespace App\{Context}\Application\Mediator\Colleague;

use App\{Context}\Application\Mediator\{Name}Mediator;

abstract class AbstractColleague implements ColleagueInterface
{
    protected ?{Name}Mediator $mediator = null;

    public function setMediator({Name}Mediator $mediator): void
    {
        $this->mediator = $mediator;
    }

    protected function notify(string $event, mixed $data = null): void
    {
        if ($this->mediator === null) {
            throw new MediatorNotSetException();
        }
        $this->mediator->notify($this, $event, $data);
    }

    protected function send(string $request, mixed $data = null): mixed
    {
        if ($this->mediator === null) {
            throw new MediatorNotSetException();
        }
        return $this->mediator->send($request, $data);
    }
}

File Placement

src/
└── {Context}/
    └── Application/
        └── Mediator/
            ├── {Name}Mediator.php           # Interface
            ├── {Name}MediatorImpl.php       # Implementation
            └── Colleague/
                ├── ColleagueInterface.php   # Base interface
                ├── AbstractColleague.php    # Base class
                └── {Colleague}.php          # Participants

tests/
└── {Context}/
    └── Application/
        └── Mediator/
            └── {Name}MediatorTest.php       # Tests

GRASP Compliance

Principle	Implementation
Low Coupling	Colleagues don't know each other
Indirection	Mediator provides indirection layer
Controller	Mediator coordinates use case flow
Pure Fabrication	Mediator is artificial coordinating class

References

See references/ for detailed documentation:

• templates.md - Full Mediator, Colleague, Command Bus, Event Mediator, Chat Room templates
• examples.md - Real-world examples