PHP7 Static Factory

Creational/StaticFactory/StaticFactory.php

@@ -3,30 +3,26 @@
 namespace DesignPatterns\Creational\StaticFactory;
 
 /**
- * Note1: Remember, static => global => evil
+ * Note1: Remember, static means global state which is evil because it can't be mocked for tests
  * Note2: Cannot be subclassed or mock-upped or have multiple different instances.
  */
-class StaticFactory
+final class StaticFactory
 {
     /**
-     * the parametrized function to get create an instance.
-     *
      * @param string $type
      *
-     * @static
-     *
-     * @throws \InvalidArgumentException
-     *
      * @return FormatterInterface
      */
-    public static function factory($type)
+    public static function factory(string $type): FormatterInterface
     {
-        $className = __NAMESPACE__.'\Format'.ucfirst($type);
-
-        if (!class_exists($className)) {
-            throw new \InvalidArgumentException('Missing format class.');
+        if ($type == 'number') {
+            return new FormatNumber();
         }
 
-        return new $className();
+        if ($type == 'string') {
+            return new FormatString();
+        }
+
+        throw new \InvalidArgumentException('Unknown format given');
     }
 }