Mediator Pattern Generator

Overview

Generates Mediator pattern components for PHP 8.5 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