Add CommandHandlerAbstract with command type validation

Author: jeckel

src/CommandHandler/CommandHandlerAbstract.php

@@ -0,0 +1,35 @@
+<?php
+declare(strict_types=1);
+/**
+ * @author Julien Mercier-Rojas <julien@jeckel-lab.fr>
+ * Created at : 14/11/2019
+ */
+
+namespace JeckelLab\CommandDispatcher\CommandHandler;
+
+use JeckelLab\CommandDispatcher\Command\CommandInterface;
+use JeckelLab\CommandDispatcher\Exception\InvalidCommandException;
+
+/**
+ * Class CommandHandlerAbstract
+ * @package JeckelLab\CommandDispatcher\CommandHandler
+ */
+abstract class CommandHandlerAbstract implements CommandHandlerInterface
+{
+    /**
+     * @param CommandInterface $command
+     * @throws InvalidCommandException
+     */
+    protected function validateCommand(CommandInterface $command): void
+    {
+        foreach (self::getHandledCommands() as $handledCommand) {
+            if ($command instanceof $handledCommand) {
+                return;
+            }
+        }
+        throw new InvalidCommandException(sprintf(
+            'Invalid command "%s" provided to handler.',
+            get_class($command)
+        ));
+    }
+}

src/CommandHandler/CommandHandlerInterface.php

@@ -9,6 +9,7 @@
 
 use JeckelLab\CommandDispatcher\Command\CommandInterface;
 use JeckelLab\CommandDispatcher\CommandResponse\CommandResponseInterface;
+use JeckelLab\CommandDispatcher\Exception\InvalidCommandException;
 
 /**
  * Interface CommandHandlerInterface
@@ -24,6 +25,7 @@ public static function getHandledCommands(): array;
     /**
      * @param CommandInterface $command
      * @return CommandResponseInterface
+     * @throws InvalidCommandException
      */
     public function __invoke(CommandInterface $command): CommandResponseInterface;
 }