feat(CommandBus): add bus

CHANGELOG.md

@@ -7,6 +7,10 @@
 
 ### New features
 
+- Add `\BSP\CommandBus`
+- Add `\BSP\Command`
+- Add `\BSP\CommandHandler`
+
 ### Bugfixes
 
 </details>

src/Command.php

@@ -0,0 +1,8 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP;
+
+interface Command
+{
+}

src/CommandBus.php

@@ -0,0 +1,17 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP;
+
+abstract class CommandBus
+{
+    /** @var CommandHandler[] */
+    protected $handlers = [];
+
+    public function execute(Command $command): void
+    {
+        if (isset($this->handlers[get_class($command)])) {
+            $this->handlers[get_class($command)]->handle($command);
+        }
+    }
+}

src/CommandHandler.php

@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP;
+
+interface CommandHandler
+{
+    public function handle(Command $command): void;
+}

tests/CommandBusTest.php

@@ -0,0 +1,28 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP\Tests;
+
+use BSP\Tests\Mock\AddSugarToCoffee;
+use BSP\Tests\Mock\AddSugarToCoffeHandler;
+use BSP\Tests\Mock\Coffee;
+use BSP\Tests\Mock\CoffeeCommandBus;
+use PHPUnit\Framework\TestCase;
+
+final class CommandBusTest extends TestCase
+{
+    public function testCommandBus(): void
+    {
+        $coffee = new Coffee();
+
+        $this->assertSame(0, $coffee::$sugars);
+
+        $command = new AddSugarToCoffee(2, $coffee);
+        $commandHandler = new AddSugarToCoffeHandler();
+        $commandBus = new CoffeeCommandBus($commandHandler);
+
+        $commandBus->execute($command);
+
+        $this->assertSame(2, $coffee::$sugars);
+    }
+}

tests/Mock/AddSugarToCoffeHandler.php

@@ -0,0 +1,19 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP\Tests\Mock;
+
+use BSP\Command;
+use BSP\CommandHandler;
+
+final class AddSugarToCoffeHandler implements CommandHandler
+{
+    /**
+     * @param AddSugarToCoffee $command
+     */
+    public function handle(Command $command): void
+    {
+        $coffee = $command->coffee();
+        $coffee::$sugars += $command->nbSugars();
+    }
+}

tests/Mock/AddSugarToCoffee.php

@@ -0,0 +1,28 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP\Tests\Mock;
+
+use BSP\Command;
+
+final class AddSugarToCoffee implements Command
+{
+    private $nbSugars;
+    private $coffee;
+
+    public function __construct(int $nbSugars, Coffee $coffee)
+    {
+        $this->nbSugars = $nbSugars;
+        $this->coffee = $coffee;
+    }
+
+    public function nbSugars(): int
+    {
+        return $this->nbSugars;
+    }
+
+    public function coffee(): Coffee
+    {
+        return $this->coffee;
+    }
+}

tests/Mock/Coffee.php

@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP\Tests\Mock;
+
+final class Coffee
+{
+    public static $sugars = 0;
+}

tests/Mock/CoffeeCommandBus.php

@@ -0,0 +1,14 @@
+<?php
+declare(strict_types=1);
+
+namespace BSP\Tests\Mock;
+
+use BSP\CommandBus;
+
+final class CoffeeCommandBus extends CommandBus
+{
+    public function __construct(AddSugarToCoffeHandler $addSugarToCoffeHandler)
+    {
+        $this->handlers[AddSugarToCoffee::class] = $addSugarToCoffeHandler;
+    }
+}