diff vendor/symfony/validator/Validator/RecursiveContextualValidator.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/symfony/validator/Validator/RecursiveContextualValidator.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,853 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[e-mail]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Validator\Validator;
+
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\Constraints\GroupSequence;
+use Symfony\Component\Validator\ConstraintValidatorFactoryInterface;
+use Symfony\Component\Validator\Context\ExecutionContext;
+use Symfony\Component\Validator\Context\ExecutionContextInterface;
+use Symfony\Component\Validator\Exception\ConstraintDefinitionException;
+use Symfony\Component\Validator\Exception\NoSuchMetadataException;
+use Symfony\Component\Validator\Exception\RuntimeException;
+use Symfony\Component\Validator\Exception\UnsupportedMetadataException;
+use Symfony\Component\Validator\Exception\ValidatorException;
+use Symfony\Component\Validator\Mapping\CascadingStrategy;
+use Symfony\Component\Validator\Mapping\ClassMetadataInterface;
+use Symfony\Component\Validator\Mapping\GenericMetadata;
+use Symfony\Component\Validator\Mapping\MetadataInterface;
+use Symfony\Component\Validator\Mapping\PropertyMetadataInterface;
+use Symfony\Component\Validator\Mapping\TraversalStrategy;
+use Symfony\Component\Validator\Mapping\Factory\MetadataFactoryInterface;
+use Symfony\Component\Validator\ObjectInitializerInterface;
+use Symfony\Component\Validator\Util\PropertyPath;
+
+/**
+ * Recursive implementation of {@link ContextualValidatorInterface}.
+ *
+ * @author Bernhard Schussek <[e-mail]>
+ */
+class RecursiveContextualValidator implements ContextualValidatorInterface
+{
+    /**
+     * @var ExecutionContextInterface
+     */
+    private $context;
+
+    /**
+     * @var string
+     */
+    private $defaultPropertyPath;
+
+    /**
+     * @var array
+     */
+    private $defaultGroups;
+
+    /**
+     * @var MetadataFactoryInterface
+     */
+    private $metadataFactory;
+
+    /**
+     * @var ConstraintValidatorFactoryInterface
+     */
+    private $validatorFactory;
+
+    /**
+     * @var ObjectInitializerInterface[]
+     */
+    private $objectInitializers;
+
+    /**
+     * Creates a validator for the given context.
+     *
+     * @param ExecutionContextInterface           $context            The execution context
+     * @param MetadataFactoryInterface            $metadataFactory    The factory for
+     *                                                                fetching the metadata
+     *                                                                of validated objects
+     * @param ConstraintValidatorFactoryInterface $validatorFactory   The factory for creating
+     *                                                                constraint validators
+     * @param ObjectInitializerInterface[]        $objectInitializers The object initializers
+     */
+    public function __construct(ExecutionContextInterface $context, MetadataFactoryInterface $metadataFactory, ConstraintValidatorFactoryInterface $validatorFactory, array $objectInitializers = array())
+    {
+        $this->context = $context;
+        $this->defaultPropertyPath = $context->getPropertyPath();
+        $this->defaultGroups = array($context->getGroup() ?: Constraint::DEFAULT_GROUP);
+        $this->metadataFactory = $metadataFactory;
+        $this->validatorFactory = $validatorFactory;
+        $this->objectInitializers = $objectInitializers;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function atPath($path)
+    {
+        $this->defaultPropertyPath = $this->context->getPropertyPath($path);
+
+        return $this;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function validate($value, $constraints = null, $groups = null)
+    {
+        $groups = $groups ? $this->normalizeGroups($groups) : $this->defaultGroups;
+
+        $previousValue = $this->context->getValue();
+        $previousObject = $this->context->getObject();
+        $previousMetadata = $this->context->getMetadata();
+        $previousPath = $this->context->getPropertyPath();
+        $previousGroup = $this->context->getGroup();
+        $previousConstraint = null;
+
+        if ($this->context instanceof ExecutionContext || method_exists($this->context, 'getConstraint')) {
+            $previousConstraint = $this->context->getConstraint();
+        }
+
+        // If explicit constraints are passed, validate the value against
+        // those constraints
+        if (null !== $constraints) {
+            // You can pass a single constraint or an array of constraints
+            // Make sure to deal with an array in the rest of the code
+            if (!is_array($constraints)) {
+                $constraints = array($constraints);
+            }
+
+            $metadata = new GenericMetadata();
+            $metadata->addConstraints($constraints);
+
+            $this->validateGenericNode(
+                $value,
+                null,
+                is_object($value) ? spl_object_hash($value) : null,
+                $metadata,
+                $this->defaultPropertyPath,
+                $groups,
+                null,
+                TraversalStrategy::IMPLICIT,
+                $this->context
+            );
+
+            $this->context->setNode($previousValue, $previousObject, $previousMetadata, $previousPath);
+            $this->context->setGroup($previousGroup);
+
+            if (null !== $previousConstraint) {
+                $this->context->setConstraint($previousConstraint);
+            }
+
+            return $this;
+        }
+
+        // If an object is passed without explicit constraints, validate that
+        // object against the constraints defined for the object's class
+        if (is_object($value)) {
+            $this->validateObject(
+                $value,
+                $this->defaultPropertyPath,
+                $groups,
+                TraversalStrategy::IMPLICIT,
+                $this->context
+            );
+
+            $this->context->setNode($previousValue, $previousObject, $previousMetadata, $previousPath);
+            $this->context->setGroup($previousGroup);
+
+            return $this;
+        }
+
+        // If an array is passed without explicit constraints, validate each
+        // object in the array
+        if (is_array($value)) {
+            $this->validateEachObjectIn(
+                $value,
+                $this->defaultPropertyPath,
+                $groups,
+                $this->context
+            );
+
+            $this->context->setNode($previousValue, $previousObject, $previousMetadata, $previousPath);
+            $this->context->setGroup($previousGroup);
+
+            return $this;
+        }
+
+        throw new RuntimeException(sprintf(
+            'Cannot validate values of type "%s" automatically. Please '.
+            'provide a constraint.',
+            gettype($value)
+        ));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function validateProperty($object, $propertyName, $groups = null)
+    {
+        $classMetadata = $this->metadataFactory->getMetadataFor($object);
+
+        if (!$classMetadata instanceof ClassMetadataInterface) {
+            throw new ValidatorException(sprintf(
+                'The metadata factory should return instances of '.
+                '"\Symfony\Component\Validator\Mapping\ClassMetadataInterface", '.
+                'got: "%s".',
+                is_object($classMetadata) ? get_class($classMetadata) : gettype($classMetadata)
+            ));
+        }
+
+        $propertyMetadatas = $classMetadata->getPropertyMetadata($propertyName);
+        $groups = $groups ? $this->normalizeGroups($groups) : $this->defaultGroups;
+        $cacheKey = spl_object_hash($object);
+        $propertyPath = PropertyPath::append($this->defaultPropertyPath, $propertyName);
+
+        $previousValue = $this->context->getValue();
+        $previousObject = $this->context->getObject();
+        $previousMetadata = $this->context->getMetadata();
+        $previousPath = $this->context->getPropertyPath();
+        $previousGroup = $this->context->getGroup();
+
+        foreach ($propertyMetadatas as $propertyMetadata) {
+            $propertyValue = $propertyMetadata->getPropertyValue($object);
+
+            $this->validateGenericNode(
+                $propertyValue,
+                $object,
+                $cacheKey.':'.get_class($object).':'.$propertyName,
+                $propertyMetadata,
+                $propertyPath,
+                $groups,
+                null,
+                TraversalStrategy::IMPLICIT,
+                $this->context
+            );
+        }
+
+        $this->context->setNode($previousValue, $previousObject, $previousMetadata, $previousPath);
+        $this->context->setGroup($previousGroup);
+
+        return $this;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function validatePropertyValue($objectOrClass, $propertyName, $value, $groups = null)
+    {
+        $classMetadata = $this->metadataFactory->getMetadataFor($objectOrClass);
+
+        if (!$classMetadata instanceof ClassMetadataInterface) {
+            throw new ValidatorException(sprintf(
+                'The metadata factory should return instances of '.
+                '"\Symfony\Component\Validator\Mapping\ClassMetadataInterface", '.
+                'got: "%s".',
+                is_object($classMetadata) ? get_class($classMetadata) : gettype($classMetadata)
+            ));
+        }
+
+        $propertyMetadatas = $classMetadata->getPropertyMetadata($propertyName);
+        $groups = $groups ? $this->normalizeGroups($groups) : $this->defaultGroups;
+
+        if (is_object($objectOrClass)) {
+            $object = $objectOrClass;
+            $cacheKey = spl_object_hash($objectOrClass);
+            $propertyPath = PropertyPath::append($this->defaultPropertyPath, $propertyName);
+        } else {
+            // $objectOrClass contains a class name
+            $object = null;
+            $cacheKey = null;
+            $propertyPath = $this->defaultPropertyPath;
+        }
+
+        $previousValue = $this->context->getValue();
+        $previousObject = $this->context->getObject();
+        $previousMetadata = $this->context->getMetadata();
+        $previousPath = $this->context->getPropertyPath();
+        $previousGroup = $this->context->getGroup();
+
+        foreach ($propertyMetadatas as $propertyMetadata) {
+            $this->validateGenericNode(
+                $value,
+                $object,
+                $cacheKey.':'.get_class($object).':'.$propertyName,
+                $propertyMetadata,
+                $propertyPath,
+                $groups,
+                null,
+                TraversalStrategy::IMPLICIT,
+                $this->context
+            );
+        }
+
+        $this->context->setNode($previousValue, $previousObject, $previousMetadata, $previousPath);
+        $this->context->setGroup($previousGroup);
+
+        return $this;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getViolations()
+    {
+        return $this->context->getViolations();
+    }
+
+    /**
+     * Normalizes the given group or list of groups to an array.
+     *
+     * @param mixed $groups The groups to normalize
+     *
+     * @return array A group array
+     */
+    protected function normalizeGroups($groups)
+    {
+        if (is_array($groups)) {
+            return $groups;
+        }
+
+        return array($groups);
+    }
+
+    /**
+     * Validates an object against the constraints defined for its class.
+     *
+     * If no metadata is available for the class, but the class is an instance
+     * of {@link \Traversable} and the selected traversal strategy allows
+     * traversal, the object will be iterated and each nested object will be
+     * validated instead.
+     *
+     * @param object                    $object            The object to cascade
+     * @param string                    $propertyPath      The current property path
+     * @param string[]                  $groups            The validated groups
+     * @param int                       $traversalStrategy The strategy for traversing the
+     *                                                     cascaded object
+     * @param ExecutionContextInterface $context           The current execution context
+     *
+     * @throws NoSuchMetadataException      If the object has no associated metadata
+     *                                      and does not implement {@link \Traversable}
+     *                                      or if traversal is disabled via the
+     *                                      $traversalStrategy argument
+     * @throws UnsupportedMetadataException If the metadata returned by the
+     *                                      metadata factory does not implement
+     *                                      {@link ClassMetadataInterface}
+     */
+    private function validateObject($object, $propertyPath, array $groups, $traversalStrategy, ExecutionContextInterface $context)
+    {
+        try {
+            $classMetadata = $this->metadataFactory->getMetadataFor($object);
+
+            if (!$classMetadata instanceof ClassMetadataInterface) {
+                throw new UnsupportedMetadataException(sprintf(
+                    'The metadata factory should return instances of '.
+                    '"Symfony\Component\Validator\Mapping\ClassMetadataInterface", '.
+                    'got: "%s".',
+                    is_object($classMetadata) ? get_class($classMetadata) : gettype($classMetadata)
+                ));
+            }
+
+            $this->validateClassNode(
+                $object,
+                spl_object_hash($object),
+                $classMetadata,
+                $propertyPath,
+                $groups,
+                null,
+                $traversalStrategy,
+                $context
+            );
+        } catch (NoSuchMetadataException $e) {
+            // Rethrow if not Traversable
+            if (!$object instanceof \Traversable) {
+                throw $e;
+            }
+
+            // Rethrow unless IMPLICIT or TRAVERSE
+            if (!($traversalStrategy & (TraversalStrategy::IMPLICIT | TraversalStrategy::TRAVERSE))) {
+                throw $e;
+            }
+
+            $this->validateEachObjectIn(
+                $object,
+                $propertyPath,
+                $groups,
+                $context
+            );
+        }
+    }
+
+    /**
+     * Validates each object in a collection against the constraints defined
+     * for their classes.
+     *
+     * If the parameter $recursive is set to true, nested {@link \Traversable}
+     * objects are iterated as well. Nested arrays are always iterated,
+     * regardless of the value of $recursive.
+     *
+     * @param array|\Traversable        $collection   The collection
+     * @param string                    $propertyPath The current property path
+     * @param string[]                  $groups       The validated groups
+     * @param ExecutionContextInterface $context      The current execution context
+     *
+     * @see ClassNode
+     * @see CollectionNode
+     */
+    private function validateEachObjectIn($collection, $propertyPath, array $groups, ExecutionContextInterface $context)
+    {
+        foreach ($collection as $key => $value) {
+            if (is_array($value)) {
+                // Arrays are always cascaded, independent of the specified
+                // traversal strategy
+                $this->validateEachObjectIn(
+                    $value,
+                    $propertyPath.'['.$key.']',
+                    $groups,
+                    $context
+                );
+
+                continue;
+            }
+
+            // Scalar and null values in the collection are ignored
+            if (is_object($value)) {
+                $this->validateObject(
+                    $value,
+                    $propertyPath.'['.$key.']',
+                    $groups,
+                    TraversalStrategy::IMPLICIT,
+                    $context
+                );
+            }
+        }
+    }
+
+    /**
+     * Validates a class node.
+     *
+     * A class node is a combination of an object with a {@link ClassMetadataInterface}
+     * instance. Each class node (conceptionally) has zero or more succeeding
+     * property nodes:
+     *
+     *     (Article:class node)
+     *                \
+     *        ($title:property node)
+     *
+     * This method validates the passed objects against all constraints defined
+     * at class level. It furthermore triggers the validation of each of the
+     * class' properties against the constraints for that property.
+     *
+     * If the selected traversal strategy allows traversal, the object is
+     * iterated and each nested object is validated against its own constraints.
+     * The object is not traversed if traversal is disabled in the class
+     * metadata.
+     *
+     * If the passed groups contain the group "Default", the validator will
+     * check whether the "Default" group has been replaced by a group sequence
+     * in the class metadata. If this is the case, the group sequence is
+     * validated instead.
+     *
+     * @param object                    $object            The validated object
+     * @param string                    $cacheKey          The key for caching
+     *                                                     the validated object
+     * @param ClassMetadataInterface    $metadata          The class metadata of
+     *                                                     the object
+     * @param string                    $propertyPath      The property path leading
+     *                                                     to the object
+     * @param string[]                  $groups            The groups in which the
+     *                                                     object should be validated
+     * @param string[]|null             $cascadedGroups    The groups in which
+     *                                                     cascaded objects should
+     *                                                     be validated
+     * @param int                       $traversalStrategy The strategy used for
+     *                                                     traversing the object
+     * @param ExecutionContextInterface $context           The current execution context
+     *
+     * @throws UnsupportedMetadataException  If a property metadata does not
+     *                                       implement {@link PropertyMetadataInterface}
+     * @throws ConstraintDefinitionException If traversal was enabled but the
+     *                                       object does not implement
+     *                                       {@link \Traversable}
+     *
+     * @see TraversalStrategy
+     */
+    private function validateClassNode($object, $cacheKey, ClassMetadataInterface $metadata = null, $propertyPath, array $groups, $cascadedGroups, $traversalStrategy, ExecutionContextInterface $context)
+    {
+        $context->setNode($object, $object, $metadata, $propertyPath);
+
+        if (!$context->isObjectInitialized($cacheKey)) {
+            foreach ($this->objectInitializers as $initializer) {
+                $initializer->initialize($object);
+            }
+
+            $context->markObjectAsInitialized($cacheKey);
+        }
+
+        foreach ($groups as $key => $group) {
+            // If the "Default" group is replaced by a group sequence, remember
+            // to cascade the "Default" group when traversing the group
+            // sequence
+            $defaultOverridden = false;
+
+            // Use the object hash for group sequences
+            $groupHash = is_object($group) ? spl_object_hash($group) : $group;
+
+            if ($context->isGroupValidated($cacheKey, $groupHash)) {
+                // Skip this group when validating the properties and when
+                // traversing the object
+                unset($groups[$key]);
+
+                continue;
+            }
+
+            $context->markGroupAsValidated($cacheKey, $groupHash);
+
+            // Replace the "Default" group by the group sequence defined
+            // for the class, if applicable.
+            // This is done after checking the cache, so that
+            // spl_object_hash() isn't called for this sequence and
+            // "Default" is used instead in the cache. This is useful
+            // if the getters below return different group sequences in
+            // every call.
+            if (Constraint::DEFAULT_GROUP === $group) {
+                if ($metadata->hasGroupSequence()) {
+                    // The group sequence is statically defined for the class
+                    $group = $metadata->getGroupSequence();
+                    $defaultOverridden = true;
+                } elseif ($metadata->isGroupSequenceProvider()) {
+                    // The group sequence is dynamically obtained from the validated
+                    // object
+                    /* @var \Symfony\Component\Validator\GroupSequenceProviderInterface $object */
+                    $group = $object->getGroupSequence();
+                    $defaultOverridden = true;
+
+                    if (!$group instanceof GroupSequence) {
+                        $group = new GroupSequence($group);
+                    }
+                }
+            }
+
+            // If the groups (=[<G1,G2>,G3,G4]) contain a group sequence
+            // (=<G1,G2>), then call validateClassNode() with each entry of the
+            // group sequence and abort if necessary (G1, G2)
+            if ($group instanceof GroupSequence) {
+                $this->stepThroughGroupSequence(
+                     $object,
+                     $object,
+                     $cacheKey,
+                     $metadata,
+                     $propertyPath,
+                     $traversalStrategy,
+                     $group,
+                     $defaultOverridden ? Constraint::DEFAULT_GROUP : null,
+                     $context
+                );
+
+                // Skip the group sequence when validating properties, because
+                // stepThroughGroupSequence() already validates the properties
+                unset($groups[$key]);
+
+                continue;
+            }
+
+            $this->validateInGroup($object, $cacheKey, $metadata, $group, $context);
+        }
+
+        // If no more groups should be validated for the property nodes,
+        // we can safely quit
+        if (0 === count($groups)) {
+            return;
+        }
+
+        // Validate all properties against their constraints
+        foreach ($metadata->getConstrainedProperties() as $propertyName) {
+            // If constraints are defined both on the getter of a property as
+            // well as on the property itself, then getPropertyMetadata()
+            // returns two metadata objects, not just one
+            foreach ($metadata->getPropertyMetadata($propertyName) as $propertyMetadata) {
+                if (!$propertyMetadata instanceof PropertyMetadataInterface) {
+                    throw new UnsupportedMetadataException(sprintf(
+                        'The property metadata instances should implement '.
+                        '"Symfony\Component\Validator\Mapping\PropertyMetadataInterface", '.
+                        'got: "%s".',
+                        is_object($propertyMetadata) ? get_class($propertyMetadata) : gettype($propertyMetadata)
+                    ));
+                }
+
+                $propertyValue = $propertyMetadata->getPropertyValue($object);
+
+                $this->validateGenericNode(
+                    $propertyValue,
+                    $object,
+                    $cacheKey.':'.get_class($object).':'.$propertyName,
+                    $propertyMetadata,
+                    PropertyPath::append($propertyPath, $propertyName),
+                    $groups,
+                    $cascadedGroups,
+                    TraversalStrategy::IMPLICIT,
+                    $context
+                );
+            }
+        }
+
+        // If no specific traversal strategy was requested when this method
+        // was called, use the traversal strategy of the class' metadata
+        if ($traversalStrategy & TraversalStrategy::IMPLICIT) {
+            $traversalStrategy = $metadata->getTraversalStrategy();
+        }
+
+        // Traverse only if IMPLICIT or TRAVERSE
+        if (!($traversalStrategy & (TraversalStrategy::IMPLICIT | TraversalStrategy::TRAVERSE))) {
+            return;
+        }
+
+        // If IMPLICIT, stop unless we deal with a Traversable
+        if ($traversalStrategy & TraversalStrategy::IMPLICIT && !$object instanceof \Traversable) {
+            return;
+        }
+
+        // If TRAVERSE, fail if we have no Traversable
+        if (!$object instanceof \Traversable) {
+            throw new ConstraintDefinitionException(sprintf(
+                'Traversal was enabled for "%s", but this class '.
+                'does not implement "\Traversable".',
+                get_class($object)
+            ));
+        }
+
+        $this->validateEachObjectIn(
+            $object,
+            $propertyPath,
+            $groups,
+            $context
+        );
+    }
+
+    /**
+     * Validates a node that is not a class node.
+     *
+     * Currently, two such node types exist:
+     *
+     *  - property nodes, which consist of the value of an object's
+     *    property together with a {@link PropertyMetadataInterface} instance
+     *  - generic nodes, which consist of a value and some arbitrary
+     *    constraints defined in a {@link MetadataInterface} container
+     *
+     * In both cases, the value is validated against all constraints defined
+     * in the passed metadata object. Then, if the value is an instance of
+     * {@link \Traversable} and the selected traversal strategy permits it,
+     * the value is traversed and each nested object validated against its own
+     * constraints. Arrays are always traversed.
+     *
+     * @param mixed                     $value             The validated value
+     * @param object|null               $object            The current object
+     * @param string                    $cacheKey          The key for caching
+     *                                                     the validated value
+     * @param MetadataInterface         $metadata          The metadata of the
+     *                                                     value
+     * @param string                    $propertyPath      The property path leading
+     *                                                     to the value
+     * @param string[]                  $groups            The groups in which the
+     *                                                     value should be validated
+     * @param string[]|null             $cascadedGroups    The groups in which
+     *                                                     cascaded objects should
+     *                                                     be validated
+     * @param int                       $traversalStrategy The strategy used for
+     *                                                     traversing the value
+     * @param ExecutionContextInterface $context           The current execution context
+     *
+     * @see TraversalStrategy
+     */
+    private function validateGenericNode($value, $object, $cacheKey, MetadataInterface $metadata = null, $propertyPath, array $groups, $cascadedGroups, $traversalStrategy, ExecutionContextInterface $context)
+    {
+        $context->setNode($value, $object, $metadata, $propertyPath);
+
+        foreach ($groups as $key => $group) {
+            if ($group instanceof GroupSequence) {
+                $this->stepThroughGroupSequence(
+                     $value,
+                     $object,
+                     $cacheKey,
+                     $metadata,
+                     $propertyPath,
+                     $traversalStrategy,
+                     $group,
+                     null,
+                     $context
+                );
+
+                // Skip the group sequence when cascading, as the cascading
+                // logic is already done in stepThroughGroupSequence()
+                unset($groups[$key]);
+
+                continue;
+            }
+
+            $this->validateInGroup($value, $cacheKey, $metadata, $group, $context);
+        }
+
+        if (0 === count($groups)) {
+            return;
+        }
+
+        if (null === $value) {
+            return;
+        }
+
+        $cascadingStrategy = $metadata->getCascadingStrategy();
+
+        // Quit unless we have an array or a cascaded object
+        if (!is_array($value) && !($cascadingStrategy & CascadingStrategy::CASCADE)) {
+            return;
+        }
+
+        // If no specific traversal strategy was requested when this method
+        // was called, use the traversal strategy of the node's metadata
+        if ($traversalStrategy & TraversalStrategy::IMPLICIT) {
+            $traversalStrategy = $metadata->getTraversalStrategy();
+        }
+
+        // The $cascadedGroups property is set, if the "Default" group is
+        // overridden by a group sequence
+        // See validateClassNode()
+        $cascadedGroups = null !== $cascadedGroups && count($cascadedGroups) > 0 ? $cascadedGroups : $groups;
+
+        if (is_array($value)) {
+            // Arrays are always traversed, independent of the specified
+            // traversal strategy
+            $this->validateEachObjectIn(
+                $value,
+                $propertyPath,
+                $cascadedGroups,
+                $context
+            );
+
+            return;
+        }
+
+        // If the value is a scalar, pass it anyway, because we want
+        // a NoSuchMetadataException to be thrown in that case
+        $this->validateObject(
+            $value,
+            $propertyPath,
+            $cascadedGroups,
+            $traversalStrategy,
+            $context
+        );
+
+        // Currently, the traversal strategy can only be TRAVERSE for a
+        // generic node if the cascading strategy is CASCADE. Thus, traversable
+        // objects will always be handled within validateObject() and there's
+        // nothing more to do here.
+
+        // see GenericMetadata::addConstraint()
+    }
+
+    /**
+     * Sequentially validates a node's value in each group of a group sequence.
+     *
+     * If any of the constraints generates a violation, subsequent groups in the
+     * group sequence are skipped.
+     *
+     * @param mixed                     $value             The validated value
+     * @param object|null               $object            The current object
+     * @param string                    $cacheKey          The key for caching
+     *                                                     the validated value
+     * @param MetadataInterface         $metadata          The metadata of the
+     *                                                     value
+     * @param string                    $propertyPath      The property path leading
+     *                                                     to the value
+     * @param int                       $traversalStrategy The strategy used for
+     *                                                     traversing the value
+     * @param GroupSequence             $groupSequence     The group sequence
+     * @param string|null               $cascadedGroup     The group that should
+     *                                                     be passed to cascaded
+     *                                                     objects instead of
+     *                                                     the group sequence
+     * @param ExecutionContextInterface $context           The execution context
+     */
+    private function stepThroughGroupSequence($value, $object, $cacheKey, MetadataInterface $metadata = null, $propertyPath, $traversalStrategy, GroupSequence $groupSequence, $cascadedGroup, ExecutionContextInterface $context)
+    {
+        $violationCount = count($context->getViolations());
+        $cascadedGroups = $cascadedGroup ? array($cascadedGroup) : null;
+
+        foreach ($groupSequence->groups as $groupInSequence) {
+            $groups = (array) $groupInSequence;
+
+            if ($metadata instanceof ClassMetadataInterface) {
+                $this->validateClassNode(
+                     $value,
+                     $cacheKey,
+                     $metadata,
+                     $propertyPath,
+                     $groups,
+                     $cascadedGroups,
+                     $traversalStrategy,
+                     $context
+                );
+            } else {
+                $this->validateGenericNode(
+                     $value,
+                     $object,
+                     $cacheKey,
+                     $metadata,
+                     $propertyPath,
+                     $groups,
+                     $cascadedGroups,
+                     $traversalStrategy,
+                     $context
+                );
+            }
+
+            // Abort sequence validation if a violation was generated
+            if (count($context->getViolations()) > $violationCount) {
+                break;
+            }
+        }
+    }
+
+    /**
+     * Validates a node's value against all constraints in the given group.
+     *
+     * @param mixed                     $value    The validated value
+     * @param string                    $cacheKey The key for caching the
+     *                                            validated value
+     * @param MetadataInterface         $metadata The metadata of the value
+     * @param string                    $group    The group to validate
+     * @param ExecutionContextInterface $context  The execution context
+     */
+    private function validateInGroup($value, $cacheKey, MetadataInterface $metadata, $group, ExecutionContextInterface $context)
+    {
+        $context->setGroup($group);
+
+        foreach ($metadata->findConstraints($group) as $constraint) {
+            // Prevent duplicate validation of constraints, in the case
+            // that constraints belong to multiple validated groups
+            if (null !== $cacheKey) {
+                $constraintHash = spl_object_hash($constraint);
+
+                if ($context->isConstraintValidated($cacheKey, $constraintHash)) {
+                    continue;
+                }
+
+                $context->markConstraintAsValidated($cacheKey, $constraintHash);
+            }
+
+            $context->setConstraint($constraint);
+
+            $validator = $this->validatorFactory->getInstance($constraint);
+            $validator->initialize($context);
+            $validator->validate($value, $constraint);
+        }
+    }
+}