diff --git a/UPGRADE.md b/UPGRADE.md
index d081b52..a35e094 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -43,6 +43,49 @@ But note that this is deprecated format and will be removed in future versions.
 In general, if new default formatting doesn't work for you - just set [your own error
 formatter](http://webonyx.github.io/graphql-php/error-handling/#custom-error-handling-and-formatting).
 
+### Breaking: Validation rules now have abstract base class
+Previously any callable was accepted by DocumentValidator as validation rule. Now only instances of 
+`GraphQL\Validator\Rules\AbstractValidationRule` are allowed.
+
+If you were using custom validation rules, just wrap them with 
+`GraphQL\Validator\Rules\CustomValidationRule` (created for backwards compatibility).
+
+Before:
+```php
+use GraphQL\Validator\DocumentValidator;
+
+$myRule = function(ValidationContext $context) {};
+DocumentValidator::validate($schema, $ast, [$myRule]);
+```
+
+After:
+```php
+use GraphQL\Validator\Rules\CustomValidationRule;
+use GraphQL\Validator\DocumentValidator;
+
+$myRule = new CustomValidationRule('MyRule', function(ValidationContext $context) {});
+DocumentValidator::validate($schema, $ast, [$myRule]);
+```
+
+Also `DocumentValidator::addRule()` signature changed. 
+
+Before the change:
+```php
+use GraphQL\Validator\DocumentValidator;
+
+$myRule = function(ValidationContext $context) {};
+DocumentValidator::addRule('MyRuleName', $myRule);
+```
+
+After the change:
+```php
+use GraphQL\Validator\DocumentValidator;
+
+$myRule = new CustomValidationRulefunction('MyRule', ValidationContext $context) {});
+DocumentValidator::addRule($myRule);
+```
+
+
 ### Breaking: AST now uses `NodeList` vs array for lists of nodes
 It helps us unserialize AST from array lazily. This change affects you only if you use `array_`
 functions with AST or mutate AST directly.
diff --git a/src/GraphQL.php b/src/GraphQL.php
index ca8ce48..6cba278 100644
--- a/src/GraphQL.php
+++ b/src/GraphQL.php
@@ -113,9 +113,18 @@ class GraphQL
                 $documentNode = Parser::parse(new Source($source ?: '', 'GraphQL'));
             }
 
-            /** @var QueryComplexity $queryComplexity */
-            $queryComplexity = DocumentValidator::getRule('QueryComplexity');
-            $queryComplexity->setRawVariableValues($variableValues);
+            // FIXME
+            if (!empty($validationRules)) {
+                foreach ($validationRules as $rule) {
+                    if ($rule instanceof QueryComplexity) {
+                        $rule->setRawVariableValues($variableValues);
+                    }
+                }
+            } else {
+                /** @var QueryComplexity $queryComplexity */
+                $queryComplexity = DocumentValidator::getRule(QueryComplexity::class);
+                $queryComplexity->setRawVariableValues($variableValues);
+            }
 
             $validationErrors = DocumentValidator::validate($schema, $documentNode, $validationRules);
 
@@ -223,7 +232,7 @@ class GraphQL
      *
      * @return Directive[]
      */
-    public static function getInternalDirectives()
+    public static function getStandardDirectives()
     {
         return array_values(Directive::getInternalDirectives());
     }
@@ -233,9 +242,17 @@ class GraphQL
      *
      * @return Type[]
      */
-    public static function getInternalTypes()
+    public static function getStandardTypes()
     {
-        return Type::getInternalTypes();
+        return array_values(Type::getInternalTypes());
+    }
+
+    /**
+     * @return array
+     */
+    public static function getStandardValidationRules()
+    {
+        return array_values(DocumentValidator::defaultRules());
     }
 
     /**
@@ -253,4 +270,15 @@ class GraphQL
     {
         Executor::setPromiseAdapter($promiseAdapter);
     }
+
+    /**
+     * Returns directives defined in GraphQL spec
+     *
+     * @deprecated Renamed to getStandardDirectives
+     * @return Directive[]
+     */
+    public static function getInternalDirectives()
+    {
+        return self::getStandardDirectives();
+    }
 }
diff --git a/src/Validator/DocumentValidator.php b/src/Validator/DocumentValidator.php
index 790b9aa..f87e708 100644
--- a/src/Validator/DocumentValidator.php
+++ b/src/Validator/DocumentValidator.php
@@ -18,6 +18,7 @@ use GraphQL\Type\Definition\NonNull;
 use GraphQL\Type\Definition\Type;
 use GraphQL\Utils\Utils;
 use GraphQL\Utils\TypeInfo;
+use GraphQL\Validator\Rules\AbstractValidationRule;
 use GraphQL\Validator\Rules\ArgumentsOfCorrectType;
 use GraphQL\Validator\Rules\DefaultValuesOfCorrectType;
 use GraphQL\Validator\Rules\DisableIntrospection;
@@ -53,6 +54,8 @@ class DocumentValidator
 
     private static $defaultRules;
 
+    private static $securityRules;
+
     private static $initRules = false;
 
     /**
@@ -63,8 +66,8 @@ class DocumentValidator
     public static function allRules()
     {
         if (!self::$initRules) {
-            self::$rules = array_merge(static::defaultRules(), self::$rules);
-            self::$initRules = true;
+            static::$rules = array_merge(static::defaultRules(), self::securityRules(), self::$rules);
+            static::$initRules = true;
         }
 
         return self::$rules;
@@ -74,64 +77,82 @@ class DocumentValidator
     {
         if (null === self::$defaultRules) {
             self::$defaultRules = [
-                'UniqueOperationNames' => new UniqueOperationNames(),
-                'LoneAnonymousOperation' => new LoneAnonymousOperation(),
-                'KnownTypeNames' => new KnownTypeNames(),
-                'FragmentsOnCompositeTypes' => new FragmentsOnCompositeTypes(),
-                'VariablesAreInputTypes' => new VariablesAreInputTypes(),
-                'ScalarLeafs' => new ScalarLeafs(),
-                'FieldsOnCorrectType' => new FieldsOnCorrectType(),
-                'UniqueFragmentNames' => new UniqueFragmentNames(),
-                'KnownFragmentNames' => new KnownFragmentNames(),
-                'NoUnusedFragments' => new NoUnusedFragments(),
-                'PossibleFragmentSpreads' => new PossibleFragmentSpreads(),
-                'NoFragmentCycles' => new NoFragmentCycles(),
-                'UniqueVariableNames' => new UniqueVariableNames(),
-                'NoUndefinedVariables' => new NoUndefinedVariables(),
-                'NoUnusedVariables' => new NoUnusedVariables(),
-                'KnownDirectives' => new KnownDirectives(),
-                'UniqueDirectivesPerLocation' => new UniqueDirectivesPerLocation(),
-                'KnownArgumentNames' => new KnownArgumentNames(),
-                'UniqueArgumentNames' => new UniqueArgumentNames(),
-                'ArgumentsOfCorrectType' => new ArgumentsOfCorrectType(),
-                'ProvidedNonNullArguments' => new ProvidedNonNullArguments(),
-                'DefaultValuesOfCorrectType' => new DefaultValuesOfCorrectType(),
-                'VariablesInAllowedPosition' => new VariablesInAllowedPosition(),
-                'OverlappingFieldsCanBeMerged' => new OverlappingFieldsCanBeMerged(),
-                'UniqueInputFieldNames' => new UniqueInputFieldNames(),
-
-                // Query Security
-                'DisableIntrospection' => new DisableIntrospection(DisableIntrospection::DISABLED), // DEFAULT DISABLED
-                'QueryDepth' => new QueryDepth(QueryDepth::DISABLED), // default disabled
-                'QueryComplexity' => new QueryComplexity(QueryComplexity::DISABLED), // default disabled
+                UniqueOperationNames::class => new UniqueOperationNames(),
+                LoneAnonymousOperation::class => new LoneAnonymousOperation(),
+                KnownTypeNames::class => new KnownTypeNames(),
+                FragmentsOnCompositeTypes::class => new FragmentsOnCompositeTypes(),
+                VariablesAreInputTypes::class => new VariablesAreInputTypes(),
+                ScalarLeafs::class => new ScalarLeafs(),
+                FieldsOnCorrectType::class => new FieldsOnCorrectType(),
+                UniqueFragmentNames::class => new UniqueFragmentNames(),
+                KnownFragmentNames::class => new KnownFragmentNames(),
+                NoUnusedFragments::class => new NoUnusedFragments(),
+                PossibleFragmentSpreads::class => new PossibleFragmentSpreads(),
+                NoFragmentCycles::class => new NoFragmentCycles(),
+                UniqueVariableNames::class => new UniqueVariableNames(),
+                NoUndefinedVariables::class => new NoUndefinedVariables(),
+                NoUnusedVariables::class => new NoUnusedVariables(),
+                KnownDirectives::class => new KnownDirectives(),
+                UniqueDirectivesPerLocation::class => new UniqueDirectivesPerLocation(),
+                KnownArgumentNames::class => new KnownArgumentNames(),
+                UniqueArgumentNames::class => new UniqueArgumentNames(),
+                ArgumentsOfCorrectType::class => new ArgumentsOfCorrectType(),
+                ProvidedNonNullArguments::class => new ProvidedNonNullArguments(),
+                DefaultValuesOfCorrectType::class => new DefaultValuesOfCorrectType(),
+                VariablesInAllowedPosition::class => new VariablesInAllowedPosition(),
+                OverlappingFieldsCanBeMerged::class => new OverlappingFieldsCanBeMerged(),
+                UniqueInputFieldNames::class => new UniqueInputFieldNames(),
             ];
         }
 
         return self::$defaultRules;
     }
 
+    /**
+     * @return array
+     */
+    public static function securityRules()
+    {
+        // This way of defining rules is deprecated
+        // When custom security rule is required - it should be just added via DocumentValidator::addRule();
+        // TODO: deprecate this
+
+        if (null === self::$securityRules) {
+            self::$securityRules = [
+                DisableIntrospection::class => new DisableIntrospection(DisableIntrospection::DISABLED), // DEFAULT DISABLED
+                QueryDepth::class => new QueryDepth(QueryDepth::DISABLED), // default disabled
+                QueryComplexity::class => new QueryComplexity(QueryComplexity::DISABLED), // default disabled
+            ];
+        }
+        return self::$securityRules;
+    }
+
     /**
      * Returns validation rule
      *
      * @param string $name
-     * @return callable|null
+     * @return AbstractValidationRule
      */
     public static function getRule($name)
     {
         $rules = static::allRules();
 
+        if (isset($rules[$name])) {
+            return $rules[$name];
+        }
+
+        $name = "GraphQL\\Validator\\Rules\\$name";
         return isset($rules[$name]) ? $rules[$name] : null ;
     }
 
     /**
      * Add rule to list of default validation rules
      *
-     * @param string $name
-     * @param callable $rule
+     * @param AbstractValidationRule $rule
      */
-    public static function addRule($name, callable $rule)
+    public static function addRule(AbstractValidationRule $rule)
     {
-        self::$rules[$name] = $rule;
+        self::$rules[$rule->getName()] = $rule;
     }
 
     /**
@@ -292,7 +313,7 @@ class DocumentValidator
      * @param Schema $schema
      * @param TypeInfo $typeInfo
      * @param DocumentNode $documentNode
-     * @param array $rules
+     * @param AbstractValidationRule[] $rules
      * @return array
      */
     public static function visitUsingRules(Schema $schema, TypeInfo $typeInfo, DocumentNode $documentNode, array $rules)
@@ -300,7 +321,7 @@ class DocumentValidator
         $context = new ValidationContext($schema, $documentNode, $typeInfo);
         $visitors = [];
         foreach ($rules as $rule) {
-            $visitors[] = $rule($context);
+            $visitors[] = $rule->getVisitor($context);
         }
         Visitor::visit($documentNode, Visitor::visitWithTypeInfo($typeInfo, Visitor::visitInParallel($visitors)));
         return $context->getErrors();
diff --git a/src/Validator/Rules/AbstractQuerySecurity.php b/src/Validator/Rules/AbstractQuerySecurity.php
index ef0d4a0..cfdc7bc 100644
--- a/src/Validator/Rules/AbstractQuerySecurity.php
+++ b/src/Validator/Rules/AbstractQuerySecurity.php
@@ -14,7 +14,7 @@ use GraphQL\Type\Introspection;
 use GraphQL\Utils\TypeInfo;
 use GraphQL\Validator\ValidationContext;
 
-abstract class AbstractQuerySecurity
+abstract class AbstractQuerySecurity extends AbstractValidationRule
 {
     const DISABLED = 0;
 
@@ -83,7 +83,7 @@ abstract class AbstractQuerySecurity
      * time we do not know what object type will be used, so we unconditionally
      * spread in all fragments.
      *
-     * @see GraphQL\Validator\Rules\OverlappingFieldsCanBeMerged
+     * @see \GraphQL\Validator\Rules\OverlappingFieldsCanBeMerged
      *
      * @param ValidationContext $context
      * @param Type|null         $parentType
diff --git a/src/Validator/Rules/AbstractValidationRule.php b/src/Validator/Rules/AbstractValidationRule.php
new file mode 100644
index 0000000..7bf9189
--- /dev/null
+++ b/src/Validator/Rules/AbstractValidationRule.php
@@ -0,0 +1,26 @@
+<?php
+namespace GraphQL\Validator\Rules;
+
+use GraphQL\Error\Error;
+use GraphQL\Validator\ValidationContext;
+
+abstract class AbstractValidationRule
+{
+    protected $name;
+
+    public function getName()
+    {
+        return $this->name ?: get_class($this);
+    }
+
+    public function __invoke(ValidationContext $context)
+    {
+        return $this->getVisitor($context);
+    }
+
+    /**
+     * @param ValidationContext $context
+     * @return Error[]
+     */
+    abstract public function getVisitor(ValidationContext $context);
+}
diff --git a/src/Validator/Rules/ArgumentsOfCorrectType.php b/src/Validator/Rules/ArgumentsOfCorrectType.php
index 3ee3162..3e37322 100644
--- a/src/Validator/Rules/ArgumentsOfCorrectType.php
+++ b/src/Validator/Rules/ArgumentsOfCorrectType.php
@@ -9,7 +9,7 @@ use GraphQL\Language\Visitor;
 use GraphQL\Validator\DocumentValidator;
 use GraphQL\Validator\ValidationContext;
 
-class ArgumentsOfCorrectType
+class ArgumentsOfCorrectType extends AbstractValidationRule
 {
     static function badValueMessage($argName, $type, $value, $verboseErrors = [])
     {
@@ -17,7 +17,7 @@ class ArgumentsOfCorrectType
         return "Argument \"$argName\" has invalid value $value.$message";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::ARGUMENT => function(ArgumentNode $argNode) use ($context) {
diff --git a/src/Validator/Rules/CustomValidationRule.php b/src/Validator/Rules/CustomValidationRule.php
new file mode 100644
index 0000000..ba7cd40
--- /dev/null
+++ b/src/Validator/Rules/CustomValidationRule.php
@@ -0,0 +1,27 @@
+<?php
+namespace GraphQL\Validator\Rules;
+
+
+use GraphQL\Error\Error;
+use GraphQL\Validator\ValidationContext;
+
+class CustomValidationRule extends AbstractValidationRule
+{
+    private $visitorFn;
+
+    public function __construct($name, callable $visitorFn)
+    {
+        $this->name = $name;
+        $this->visitorFn = $visitorFn;
+    }
+
+    /**
+     * @param ValidationContext $context
+     * @return Error[]
+     */
+    public function getVisitor(ValidationContext $context)
+    {
+        $fn = $this->visitorFn;
+        return $fn($context);
+    }
+}
diff --git a/src/Validator/Rules/DefaultValuesOfCorrectType.php b/src/Validator/Rules/DefaultValuesOfCorrectType.php
index b8f1b1d..792acd7 100644
--- a/src/Validator/Rules/DefaultValuesOfCorrectType.php
+++ b/src/Validator/Rules/DefaultValuesOfCorrectType.php
@@ -12,7 +12,7 @@ use GraphQL\Type\Definition\NonNull;
 use GraphQL\Validator\DocumentValidator;
 use GraphQL\Validator\ValidationContext;
 
-class DefaultValuesOfCorrectType
+class DefaultValuesOfCorrectType extends AbstractValidationRule
 {
     static function badValueForDefaultArgMessage($varName, $type, $value, $verboseErrors = null)
     {
@@ -27,7 +27,7 @@ class DefaultValuesOfCorrectType
         "Perhaps you meant to use type $guessType.";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::VARIABLE_DEFINITION => function(VariableDefinitionNode $varDefNode) use ($context) {
diff --git a/src/Validator/Rules/DisableIntrospection.php b/src/Validator/Rules/DisableIntrospection.php
index f820375..dec9f37 100644
--- a/src/Validator/Rules/DisableIntrospection.php
+++ b/src/Validator/Rules/DisableIntrospection.php
@@ -11,7 +11,7 @@ class DisableIntrospection extends AbstractQuerySecurity
     const ENABLED = 1;
     private $isEnabled;
 
-    public function __construct($enabled)
+    public function __construct($enabled = self::ENABLED)
     {
         $this->setEnabled($enabled);
     }
@@ -31,7 +31,7 @@ class DisableIntrospection extends AbstractQuerySecurity
         return $this->isEnabled !== static::DISABLED;
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return $this->invokeIfNeeded(
             $context,
diff --git a/src/Validator/Rules/FieldsOnCorrectType.php b/src/Validator/Rules/FieldsOnCorrectType.php
index 7f339e7..26ee748 100644
--- a/src/Validator/Rules/FieldsOnCorrectType.php
+++ b/src/Validator/Rules/FieldsOnCorrectType.php
@@ -7,7 +7,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Utils\Utils;
 use GraphQL\Validator\ValidationContext;
 
-class FieldsOnCorrectType
+class FieldsOnCorrectType extends AbstractValidationRule
 {
     static function undefinedFieldMessage($field, $type, array $suggestedTypes = [])
     {
@@ -29,7 +29,7 @@ class FieldsOnCorrectType
         return $message;
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::FIELD => function(FieldNode $node) use ($context) {
diff --git a/src/Validator/Rules/FragmentsOnCompositeTypes.php b/src/Validator/Rules/FragmentsOnCompositeTypes.php
index 1d6e450..f2731d0 100644
--- a/src/Validator/Rules/FragmentsOnCompositeTypes.php
+++ b/src/Validator/Rules/FragmentsOnCompositeTypes.php
@@ -10,7 +10,7 @@ use GraphQL\Type\Definition\Type;
 use GraphQL\Utils\TypeInfo;
 use GraphQL\Validator\ValidationContext;
 
-class FragmentsOnCompositeTypes
+class FragmentsOnCompositeTypes extends AbstractValidationRule
 {
     static function inlineFragmentOnNonCompositeErrorMessage($type)
     {
@@ -22,7 +22,7 @@ class FragmentsOnCompositeTypes
         return "Fragment \"$fragName\" cannot condition on non composite type \"$type\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::INLINE_FRAGMENT => function(InlineFragmentNode $node) use ($context) {
diff --git a/src/Validator/Rules/KnownArgumentNames.php b/src/Validator/Rules/KnownArgumentNames.php
index b2dfdb8..78ee3f9 100644
--- a/src/Validator/Rules/KnownArgumentNames.php
+++ b/src/Validator/Rules/KnownArgumentNames.php
@@ -7,7 +7,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Utils\Utils;
 use GraphQL\Validator\ValidationContext;
 
-class KnownArgumentNames
+class KnownArgumentNames extends AbstractValidationRule
 {
     public static function unknownArgMessage($argName, $fieldName, $type)
     {
@@ -19,7 +19,7 @@ class KnownArgumentNames
         return "Unknown argument \"$argName\" on directive \"@$directiveName\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::ARGUMENT => function(ArgumentNode $node, $key, $parent, $path, $ancestors) use ($context) {
diff --git a/src/Validator/Rules/KnownDirectives.php b/src/Validator/Rules/KnownDirectives.php
index 37c2584..3593f62 100644
--- a/src/Validator/Rules/KnownDirectives.php
+++ b/src/Validator/Rules/KnownDirectives.php
@@ -9,7 +9,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Validator\ValidationContext;
 use GraphQL\Type\Definition\DirectiveLocation;
 
-class KnownDirectives
+class KnownDirectives extends AbstractValidationRule
 {
     static function unknownDirectiveMessage($directiveName)
     {
@@ -21,7 +21,7 @@ class KnownDirectives
         return "Directive \"$directiveName\" may not be used on \"$location\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::DIRECTIVE => function (DirectiveNode $node, $key, $parent, $path, $ancestors) use ($context) {
diff --git a/src/Validator/Rules/KnownFragmentNames.php b/src/Validator/Rules/KnownFragmentNames.php
index 39e5858..35645db 100644
--- a/src/Validator/Rules/KnownFragmentNames.php
+++ b/src/Validator/Rules/KnownFragmentNames.php
@@ -8,14 +8,14 @@ use GraphQL\Language\AST\Node;
 use GraphQL\Language\AST\NodeKind;
 use GraphQL\Validator\ValidationContext;
 
-class KnownFragmentNames
+class KnownFragmentNames extends AbstractValidationRule
 {
     static function unknownFragmentMessage($fragName)
     {
         return "Unknown fragment \"$fragName\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::FRAGMENT_SPREAD => function(FragmentSpreadNode $node) use ($context) {
diff --git a/src/Validator/Rules/KnownTypeNames.php b/src/Validator/Rules/KnownTypeNames.php
index 7ca22d8..71fa60a 100644
--- a/src/Validator/Rules/KnownTypeNames.php
+++ b/src/Validator/Rules/KnownTypeNames.php
@@ -8,14 +8,14 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\Visitor;
 use GraphQL\Validator\ValidationContext;
 
-class KnownTypeNames
+class KnownTypeNames extends AbstractValidationRule
 {
     static function unknownTypeMessage($type)
     {
         return "Unknown type \"$type\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $skip = function() {return Visitor::skipNode();};
 
diff --git a/src/Validator/Rules/LoneAnonymousOperation.php b/src/Validator/Rules/LoneAnonymousOperation.php
index 1d735b5..f02025f 100644
--- a/src/Validator/Rules/LoneAnonymousOperation.php
+++ b/src/Validator/Rules/LoneAnonymousOperation.php
@@ -15,14 +15,14 @@ use GraphQL\Validator\ValidationContext;
  * A GraphQL document is only valid if when it contains an anonymous operation
  * (the query short-hand) that it contains only that one operation definition.
  */
-class LoneAnonymousOperation
+class LoneAnonymousOperation extends AbstractValidationRule
 {
     static function anonOperationNotAloneMessage()
     {
         return 'This anonymous operation must be the only defined operation.';
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $operationCount = 0;
         return [
diff --git a/src/Validator/Rules/NoFragmentCycles.php b/src/Validator/Rules/NoFragmentCycles.php
index 06d9f18..cf3eb0a 100644
--- a/src/Validator/Rules/NoFragmentCycles.php
+++ b/src/Validator/Rules/NoFragmentCycles.php
@@ -1,11 +1,4 @@
 <?php
-/**
- * Created by PhpStorm.
- * User: Vladimir
- * Date: 11.07.2015
- * Time: 18:54
- */
-
 namespace GraphQL\Validator\Rules;
 
 
@@ -18,7 +11,7 @@ use GraphQL\Language\Visitor;
 use GraphQL\Utils\Utils;
 use GraphQL\Validator\ValidationContext;
 
-class NoFragmentCycles
+class NoFragmentCycles extends AbstractValidationRule
 {
     static function cycleErrorMessage($fragName, array $spreadNames = [])
     {
@@ -32,7 +25,7 @@ class NoFragmentCycles
 
     public $spreadPathIndexByName;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         // Tracks already visited fragments to maintain O(N) and to ensure that cycles
         // are not redundantly reported.
diff --git a/src/Validator/Rules/NoUndefinedVariables.php b/src/Validator/Rules/NoUndefinedVariables.php
index c9486d9..42aa3cc 100644
--- a/src/Validator/Rules/NoUndefinedVariables.php
+++ b/src/Validator/Rules/NoUndefinedVariables.php
@@ -15,7 +15,7 @@ use GraphQL\Validator\ValidationContext;
  *
  * @package GraphQL\Validator\Rules
  */
-class NoUndefinedVariables
+class NoUndefinedVariables extends AbstractValidationRule
 {
     static function undefinedVarMessage($varName, $opName = null)
     {
@@ -24,7 +24,7 @@ class NoUndefinedVariables
             : "Variable \"$$varName\" is not defined.";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $variableNameDefined = [];
 
diff --git a/src/Validator/Rules/NoUnusedFragments.php b/src/Validator/Rules/NoUnusedFragments.php
index 53d7b6b..2168586 100644
--- a/src/Validator/Rules/NoUnusedFragments.php
+++ b/src/Validator/Rules/NoUnusedFragments.php
@@ -7,7 +7,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\Visitor;
 use GraphQL\Validator\ValidationContext;
 
-class NoUnusedFragments
+class NoUnusedFragments extends AbstractValidationRule
 {
     static function unusedFragMessage($fragName)
     {
@@ -18,7 +18,7 @@ class NoUnusedFragments
 
     public $fragmentDefs;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->operationDefs = [];
         $this->fragmentDefs = [];
diff --git a/src/Validator/Rules/NoUnusedVariables.php b/src/Validator/Rules/NoUnusedVariables.php
index cd939a2..c004623 100644
--- a/src/Validator/Rules/NoUnusedVariables.php
+++ b/src/Validator/Rules/NoUnusedVariables.php
@@ -6,7 +6,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\AST\OperationDefinitionNode;
 use GraphQL\Validator\ValidationContext;
 
-class NoUnusedVariables
+class NoUnusedVariables extends AbstractValidationRule
 {
     static function unusedVariableMessage($varName, $opName = null)
     {
@@ -17,7 +17,7 @@ class NoUnusedVariables
 
     public $variableDefs;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->variableDefs = [];
 
diff --git a/src/Validator/Rules/OverlappingFieldsCanBeMerged.php b/src/Validator/Rules/OverlappingFieldsCanBeMerged.php
index db907c9..d0a0fb0 100644
--- a/src/Validator/Rules/OverlappingFieldsCanBeMerged.php
+++ b/src/Validator/Rules/OverlappingFieldsCanBeMerged.php
@@ -23,7 +23,7 @@ use GraphQL\Utils\PairSet;
 use GraphQL\Utils\TypeInfo;
 use GraphQL\Validator\ValidationContext;
 
-class OverlappingFieldsCanBeMerged
+class OverlappingFieldsCanBeMerged extends AbstractValidationRule
 {
     static function fieldsConflictMessage($responseName, $reason)
     {
@@ -49,7 +49,7 @@ class OverlappingFieldsCanBeMerged
      */
     public $comparedSet;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->comparedSet = new PairSet();
 
diff --git a/src/Validator/Rules/PossibleFragmentSpreads.php b/src/Validator/Rules/PossibleFragmentSpreads.php
index 598d591..fec7dc7 100644
--- a/src/Validator/Rules/PossibleFragmentSpreads.php
+++ b/src/Validator/Rules/PossibleFragmentSpreads.php
@@ -16,7 +16,7 @@ use GraphQL\Type\Definition\UnionType;
 use GraphQL\Validator\ValidationContext;
 use GraphQL\Utils\TypeInfo;
 
-class PossibleFragmentSpreads
+class PossibleFragmentSpreads extends AbstractValidationRule
 {
     static function typeIncompatibleSpreadMessage($fragName, $parentType, $fragType)
     {
@@ -28,7 +28,7 @@ class PossibleFragmentSpreads
         return "Fragment cannot be spread here as objects of type \"$parentType\" can never be of type \"$fragType\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::INLINE_FRAGMENT => function(InlineFragmentNode $node) use ($context) {
diff --git a/src/Validator/Rules/ProvidedNonNullArguments.php b/src/Validator/Rules/ProvidedNonNullArguments.php
index 1fe8bfc..a0370f9 100644
--- a/src/Validator/Rules/ProvidedNonNullArguments.php
+++ b/src/Validator/Rules/ProvidedNonNullArguments.php
@@ -12,7 +12,7 @@ use GraphQL\Type\Definition\NonNull;
 use GraphQL\Utils\Utils;
 use GraphQL\Validator\ValidationContext;
 
-class ProvidedNonNullArguments
+class ProvidedNonNullArguments extends AbstractValidationRule
 {
     static function missingFieldArgMessage($fieldName, $argName, $type)
     {
@@ -24,7 +24,7 @@ class ProvidedNonNullArguments
         return "Directive \"@$directiveName\" argument \"$argName\" of type \"$type\" is required but not provided.";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::FIELD => [
diff --git a/src/Validator/Rules/QueryComplexity.php b/src/Validator/Rules/QueryComplexity.php
index 0a00fe2..f20334e 100644
--- a/src/Validator/Rules/QueryComplexity.php
+++ b/src/Validator/Rules/QueryComplexity.php
@@ -31,9 +31,9 @@ class QueryComplexity extends AbstractQuerySecurity
      */
     private $context;
 
-    public function __construct($maxQueryDepth)
+    public function __construct($maxQueryComplexity)
     {
-        $this->setMaxQueryComplexity($maxQueryDepth);
+        $this->setMaxQueryComplexity($maxQueryComplexity);
     }
 
     public static function maxQueryComplexityErrorMessage($max, $count)
@@ -68,7 +68,7 @@ class QueryComplexity extends AbstractQuerySecurity
         return $this->rawVariableValues;
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->context = $context;
 
diff --git a/src/Validator/Rules/QueryDepth.php b/src/Validator/Rules/QueryDepth.php
index ca0a8df..5fb7065 100644
--- a/src/Validator/Rules/QueryDepth.php
+++ b/src/Validator/Rules/QueryDepth.php
@@ -45,7 +45,7 @@ class QueryDepth extends AbstractQuerySecurity
         return sprintf('Max query depth should be %d but got %d.', $max, $count);
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return $this->invokeIfNeeded(
             $context,
diff --git a/src/Validator/Rules/ScalarLeafs.php b/src/Validator/Rules/ScalarLeafs.php
index de1f7d6..670403d 100644
--- a/src/Validator/Rules/ScalarLeafs.php
+++ b/src/Validator/Rules/ScalarLeafs.php
@@ -7,7 +7,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Type\Definition\Type;
 use GraphQL\Validator\ValidationContext;
 
-class ScalarLeafs
+class ScalarLeafs extends AbstractValidationRule
 {
     static function noSubselectionAllowedMessage($field, $type)
     {
@@ -19,7 +19,7 @@ class ScalarLeafs
         return "Field \"$field\" of type \"$type\" must have a sub selection.";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::FIELD => function(FieldNode $node) use ($context) {
diff --git a/src/Validator/Rules/UniqueArgumentNames.php b/src/Validator/Rules/UniqueArgumentNames.php
index 6c4f5c2..7c6eef1 100644
--- a/src/Validator/Rules/UniqueArgumentNames.php
+++ b/src/Validator/Rules/UniqueArgumentNames.php
@@ -8,7 +8,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\Visitor;
 use GraphQL\Validator\ValidationContext;
 
-class UniqueArgumentNames
+class UniqueArgumentNames extends AbstractValidationRule
 {
     static function duplicateArgMessage($argName)
     {
@@ -17,7 +17,7 @@ class UniqueArgumentNames
 
     public $knownArgNames;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->knownArgNames = [];
 
diff --git a/src/Validator/Rules/UniqueDirectivesPerLocation.php b/src/Validator/Rules/UniqueDirectivesPerLocation.php
index f389b12..08d778a 100644
--- a/src/Validator/Rules/UniqueDirectivesPerLocation.php
+++ b/src/Validator/Rules/UniqueDirectivesPerLocation.php
@@ -6,14 +6,14 @@ use GraphQL\Language\AST\DirectiveNode;
 use GraphQL\Language\AST\Node;
 use GraphQL\Validator\ValidationContext;
 
-class UniqueDirectivesPerLocation
+class UniqueDirectivesPerLocation extends AbstractValidationRule
 {
     static function duplicateDirectiveMessage($directiveName)
     {
         return 'The directive "'.$directiveName.'" can only be used once at this location.';
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             'enter' => function(Node $node) use ($context) {
diff --git a/src/Validator/Rules/UniqueFragmentNames.php b/src/Validator/Rules/UniqueFragmentNames.php
index 12e92a5..af5706b 100644
--- a/src/Validator/Rules/UniqueFragmentNames.php
+++ b/src/Validator/Rules/UniqueFragmentNames.php
@@ -9,7 +9,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\Visitor;
 use GraphQL\Validator\ValidationContext;
 
-class UniqueFragmentNames
+class UniqueFragmentNames extends AbstractValidationRule
 {
     static function duplicateFragmentNameMessage($fragName)
     {
@@ -18,7 +18,7 @@ class UniqueFragmentNames
 
     public $knownFragmentNames;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->knownFragmentNames = [];
 
diff --git a/src/Validator/Rules/UniqueInputFieldNames.php b/src/Validator/Rules/UniqueInputFieldNames.php
index cbc7b73..3e60df8 100644
--- a/src/Validator/Rules/UniqueInputFieldNames.php
+++ b/src/Validator/Rules/UniqueInputFieldNames.php
@@ -8,7 +8,7 @@ use GraphQL\Language\AST\ObjectFieldNode;
 use GraphQL\Language\Visitor;
 use GraphQL\Validator\ValidationContext;
 
-class UniqueInputFieldNames
+class UniqueInputFieldNames extends AbstractValidationRule
 {
     static function duplicateInputFieldMessage($fieldName)
     {
@@ -18,7 +18,7 @@ class UniqueInputFieldNames
     public $knownNames;
     public $knownNameStack;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->knownNames = [];
         $this->knownNameStack = [];
diff --git a/src/Validator/Rules/UniqueOperationNames.php b/src/Validator/Rules/UniqueOperationNames.php
index 30e494f..17fff14 100644
--- a/src/Validator/Rules/UniqueOperationNames.php
+++ b/src/Validator/Rules/UniqueOperationNames.php
@@ -8,7 +8,7 @@ use GraphQL\Language\AST\OperationDefinitionNode;
 use GraphQL\Language\Visitor;
 use GraphQL\Validator\ValidationContext;
 
-class UniqueOperationNames
+class UniqueOperationNames extends AbstractValidationRule
 {
     static function duplicateOperationNameMessage($operationName)
     {
@@ -17,7 +17,7 @@ class UniqueOperationNames
 
     public $knownOperationNames;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->knownOperationNames = [];
 
diff --git a/src/Validator/Rules/UniqueVariableNames.php b/src/Validator/Rules/UniqueVariableNames.php
index ee6267a..cdbb1ca 100644
--- a/src/Validator/Rules/UniqueVariableNames.php
+++ b/src/Validator/Rules/UniqueVariableNames.php
@@ -7,7 +7,7 @@ use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\AST\VariableDefinitionNode;
 use GraphQL\Validator\ValidationContext;
 
-class UniqueVariableNames
+class UniqueVariableNames extends AbstractValidationRule
 {
     static function duplicateVariableMessage($variableName)
     {
@@ -16,7 +16,7 @@ class UniqueVariableNames
 
     public $knownVariableNames;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         $this->knownVariableNames = [];
 
diff --git a/src/Validator/Rules/VariablesAreInputTypes.php b/src/Validator/Rules/VariablesAreInputTypes.php
index 4db3193..a8f1bbf 100644
--- a/src/Validator/Rules/VariablesAreInputTypes.php
+++ b/src/Validator/Rules/VariablesAreInputTypes.php
@@ -12,14 +12,14 @@ use GraphQL\Type\Definition\Type;
 use GraphQL\Utils\TypeInfo;
 use GraphQL\Validator\ValidationContext;
 
-class VariablesAreInputTypes
+class VariablesAreInputTypes extends AbstractValidationRule
 {
     static function nonInputTypeOnVarMessage($variableName, $typeName)
     {
         return "Variable \"\$$variableName\" cannot be non-input type \"$typeName\".";
     }
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::VARIABLE_DEFINITION => function(VariableDefinitionNode $node) use ($context) {
diff --git a/src/Validator/Rules/VariablesInAllowedPosition.php b/src/Validator/Rules/VariablesInAllowedPosition.php
index e29ac57..c0608ff 100644
--- a/src/Validator/Rules/VariablesInAllowedPosition.php
+++ b/src/Validator/Rules/VariablesInAllowedPosition.php
@@ -11,7 +11,7 @@ use GraphQL\Utils\TypeComparators;
 use GraphQL\Utils\TypeInfo;
 use GraphQL\Validator\ValidationContext;
 
-class VariablesInAllowedPosition
+class VariablesInAllowedPosition extends AbstractValidationRule
 {
     static function badVarPosMessage($varName, $varType, $expectedType)
     {
@@ -21,7 +21,7 @@ class VariablesInAllowedPosition
 
     public $varDefMap;
 
-    public function __invoke(ValidationContext $context)
+    public function getVisitor(ValidationContext $context)
     {
         return [
             NodeKind::OPERATION_DEFINITION => [
diff --git a/tests/Server/QueryExecutionTest.php b/tests/Server/QueryExecutionTest.php
index a543327..16c99a7 100644
--- a/tests/Server/QueryExecutionTest.php
+++ b/tests/Server/QueryExecutionTest.php
@@ -17,6 +17,7 @@ use GraphQL\Server\ServerConfig;
 use GraphQL\Type\Definition\ObjectType;
 use GraphQL\Type\Definition\Type;
 use GraphQL\Validator\DocumentValidator;
+use GraphQL\Validator\Rules\CustomValidationRule;
 use GraphQL\Validator\ValidationContext;
 
 class QueryExecutionTest extends \PHPUnit_Framework_TestCase
@@ -219,10 +220,10 @@ class QueryExecutionTest extends \PHPUnit_Framework_TestCase
         $called = false;
 
         $rules = [
-            function() use (&$called) {
+            new CustomValidationRule('SomeRule', function() use (&$called) {
                 $called = true;
                 return [];
-            }
+            })
         ];
 
         $this->config->setValidationRules($rules);
@@ -268,9 +269,9 @@ class QueryExecutionTest extends \PHPUnit_Framework_TestCase
             } else {
                 $called2 = true;
                 return [
-                    function(ValidationContext $context) {
+                    new CustomValidationRule('MyRule', function(ValidationContext $context) {
                         $context->reportError(new Error("This is the error we are looking for!"));
-                    }
+                    })
                 ];
             }
         });
diff --git a/tests/Validator/QueryComplexityTest.php b/tests/Validator/QueryComplexityTest.php
index 1dd3e37..fb1a8d7 100644
--- a/tests/Validator/QueryComplexityTest.php
+++ b/tests/Validator/QueryComplexityTest.php
@@ -5,6 +5,7 @@ use GraphQL\Error\Error;
 use GraphQL\Language\AST\NodeKind;
 use GraphQL\Language\Parser;
 use GraphQL\Validator\DocumentValidator;
+use GraphQL\Validator\Rules\CustomValidationRule;
 use GraphQL\Validator\Rules\QueryComplexity;
 use GraphQL\Validator\ValidationContext;
 
@@ -159,7 +160,7 @@ class QueryComplexityTest extends AbstractQuerySecurityTest
         $query = 'query MyQuery { human(name: INVALID_VALUE) { dogs {name} } }';
 
         $reportedError = new Error("OtherValidatorError");
-        $otherRule = function(ValidationContext $context) use ($reportedError) {
+        $otherRule = new CustomValidationRule('otherRule', function(ValidationContext $context) use ($reportedError) {
             return [
                 NodeKind::OPERATION_DEFINITION => [
                     'leave' => function() use ($context, $reportedError) {
@@ -167,7 +168,7 @@ class QueryComplexityTest extends AbstractQuerySecurityTest
                     }
                 ]
             ];
-        };
+        });
 
         $errors = DocumentValidator::validate(
             QuerySecuritySchema::buildSchema(),
diff --git a/tests/Validator/ValidationTest.php b/tests/Validator/ValidationTest.php
index 55f1059..d5fd855 100644
--- a/tests/Validator/ValidationTest.php
+++ b/tests/Validator/ValidationTest.php
@@ -1,6 +1,9 @@
 <?php
 namespace GraphQL\Tests\Validator;
 
+use GraphQL\Validator\DocumentValidator;
+use GraphQL\Validator\Rules\QueryComplexity;
+
 class ValidationTest extends TestCase
 {
     // Validate: Supports full validation
@@ -23,7 +26,16 @@ class ValidationTest extends TestCase
           }
         ');
     }
+/*
+    public function testAllowsSettingRulesGlobally()
+    {
+        $rule = new QueryComplexity(0);
 
+        DocumentValidator::addRule($rule);
+        $instance = DocumentValidator::getRule(QueryComplexity::class);
+        $this->assertSame($rule, $instance);
+    }
+*/
     public function testPassesValidationWithEmptyRules()
     {
         $query = '{invalid}';