add example on how to use the static method loader

mickaelandrieu · weaverryan · commit 07a344c4bcc7 · 2016-07-31T09:40:01.000-04:00
diff --git a/components/validator/builtin_validators.rst b/components/validator/builtin_validators.rst
@@ -2,4 +2,7 @@
     single: Validator; Built In validators
 
 Built In validators
-===================
+===================
+
+For each validation rule, the component ships a Constraint class and its associated Validator class.
+The Constraint object describes the rule to check and the Validator implementation runs the validation logic.
diff --git a/components/validator/resources.rst b/components/validator/resources.rst
@@ -34,7 +34,25 @@ method of the Validator builder::
         ->getValidator();
 
 Now, the retrieved ``Validator`` tries to find the ``loadValidatorMetadata()``
-method of the class to validate to load its metadata.
+method of the class to validate to load its metadata::
+
+    use Symfony\Component\Validator\Mapping\ClassMetadata;
+    use Symfony\Component\Validator\Constraints\NotBlank;
+    use Symfony\Component\Validator\Constraints\Length;
+
+    class User
+    {
+        protected $name;
+
+        public static function loadValidatorMatadata(ClassMetadata $metadata)
+        {
+            $metadata->addPropertyConstraint('name', new NotBlank());
+            $metadata->addPropertyConstraint('name', new Length(array(
+                'min' => 5,
+                'max' => 20,
+            )));
+        }
+    }
 
 .. tip::
 
