diff --git a/core/lib/Drupal/Core/TypedData/AccessibleInterface.php b/core/lib/Drupal/Core/TypedData/AccessibleInterface.php
new file mode 100644
index 0000000..3c42f7a
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/AccessibleInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\AccessibleInterface.
+ */
+
+namespace Drupal\Core\TypedData;
+
+/**
+ * Interface for checking access.
+ */
+interface AccessibleInterface {
+
+  /**
+   * Check data value access.
+   *
+   * @param \Drupal\user\User $account
+   *   (optional) The user account to check access for. Defaults to the current
+   *   user.
+   *
+   * @return bool
+   *   Whether the given user has access.
+   */
+  public function access(\Drupal\user\User $account = NULL);
+
+}
diff --git a/core/lib/Drupal/Core/TypedData/ListInterface.php b/core/lib/Drupal/Core/TypedData/ListInterface.php
new file mode 100644
index 0000000..4803330
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/ListInterface.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\ListInterface.
+ */
+
+namespace Drupal\Core\TypedData;
+use ArrayAccess;
+use IteratorAggregate;
+use Countable;
+
+/**
+ * Interface for a list of typed data.
+ */
+interface ListInterface extends ArrayAccess, IteratorAggregate , Countable {
+
+  /**
+   * Determines whether the list contains any non-empty items.
+   *
+   * @return boolean
+   *   TRUE if the list is empty, FALSE otherwise.
+   */
+  public function isEmpty();
+}
diff --git a/core/lib/Drupal/Core/TypedData/MissingContextException.php b/core/lib/Drupal/Core/TypedData/MissingContextException.php
new file mode 100644
index 0000000..91fcbd7
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/MissingContextException.php
@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\MissingContextException.
+ */
+
+namespace Drupal\Core\TypedData;
+use Exception;
+
+/**
+ * Exception thrown when data wrappers miss contextual information.
+ */
+class MissingContextException extends Exception { }
diff --git a/core/lib/Drupal/Core/TypedData/Primitive.php b/core/lib/Drupal/Core/TypedData/Primitive.php
new file mode 100644
index 0000000..461d5fb
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Primitive.php
@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Primitive.
+ */
+
+namespace Drupal\Core\TypedData;
+
+/**
+ * Class that holds constants for all primitive data types.
+ */
+final class Primitive {
+
+  /**
+   * The BOOLEAN primitive data type.
+   */
+  const BOOLEAN = 1;
+
+  /**
+   * The STRING primitive data type.
+   */
+  const STRING = 2;
+
+  /**
+   * The INTEGER primitive data type.
+   */
+  const INTEGER = 3;
+
+  /**
+   * The DECIMAL primitive data type.
+   */
+  const DECIMAL = 4;
+
+  /**
+   * The DATE primitive data type.
+   */
+  const DATE = 5;
+
+  /**
+   * The DURATION primitive data type.
+   */
+  const DURATION = 6;
+
+  /**
+   * The URI primitive data type.
+   */
+  const URI = 7;
+
+  /**
+   * The BINARY primitive data type.
+   */
+  const BINARY = 8;
+
+}
diff --git a/core/lib/Drupal/Core/TypedData/ReadOnlyException.php b/core/lib/Drupal/Core/TypedData/ReadOnlyException.php
new file mode 100644
index 0000000..d116f22
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/ReadOnlyException.php
@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\ReadOnlyException.
+ */
+
+namespace Drupal\Core\TypedData;
+use Exception;
+
+/**
+ * Exception thrown when trying to write or set ready-only data.
+ */
+class ReadOnlyException extends Exception { }
diff --git a/core/lib/Drupal/Core/TypedData/StructureInterface.php b/core/lib/Drupal/Core/TypedData/StructureInterface.php
new file mode 100644
index 0000000..1aba93f
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/StructureInterface.php
@@ -0,0 +1,115 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\StructureInterface.
+ */
+
+namespace Drupal\Core\TypedData;
+use IteratorAggregate;
+
+/**
+ * Interface for data structures that contain properties.
+ *
+ * This is implemented by entities as well as by EntityPropertyItem classes of
+ * the entity.module.
+ */
+interface StructureInterface extends IteratorAggregate  {
+
+  /**
+   * Gets a property.
+   *
+   * @param $property_name
+   *   The name of the property to get; e.g., 'title' or 'name'.
+   *
+   * @throws \InvalidArgumentException
+   *   If an invalid property name is given.
+   *
+   * @return \Drupal\Core\TypedData\WrapperInterface
+   *   The property object.
+   */
+  public function get($property_name);
+
+  /**
+   * Sets a property.
+   *
+   * @param $property_name
+   *   The name of the property to set; e.g., 'title' or 'name'.
+   * @param $value
+   *   The value to set, or NULL to unset the property.
+   *
+   * @throws \InvalidArgumentException
+   *   If an invalid property name is given.
+   *
+   * @return \Drupal\Core\TypedData\WrapperInterface
+   *   The property object.
+   */
+  public function set($property_name, $value);
+
+  /**
+   * Gets an array of properties.
+   *
+   * @param bool $include_computed
+   *   If set to TRUE, computed properties are included. Defaults to FALSE.
+   *
+   * @return array
+   *   An array of property objects implementing the WrapperInterface, keyed
+   *   by property name.
+   */
+  public function getProperties($include_computed = FALSE);
+
+  /**
+   * Sets an array of properties.
+   *
+   * @param array
+   *   The array of properties to set. The array has to consist of property
+   *   values or property objects implementing the WrapperInterface and must
+   *   be keyed by property name.
+   *
+   * @throws \InvalidArgumentException
+   *   If an not existing property is passed.
+   * @throws \Drupal\Core\TypedData\ReadOnlyException
+   *   If a read-only property is set.
+   */
+  public function setProperties($properties);
+
+  /**
+   * Gets the definition of a contained property.
+   *
+   * @param string $name
+   *   The name of property.
+   *
+   * @return array|FALSE
+   *   The definition of the property or FALSE if the property does not exist.
+   */
+  public function getPropertyDefinition($name);
+
+  /**
+   * Gets an array property definitions of contained properties.
+   *
+   * @param array $definition
+   *   The definition of the container's property, e.g. the definition of an
+   *   entity reference property.
+   *
+   * @return array
+   *   An array of property definitions of contained properties, keyed by
+   *   property name.
+   */
+  public function getPropertyDefinitions();
+
+  /**
+   * Gets the plain values of the contained properties.
+   *
+   * @return array
+   *   An array keyed by property name containing the plain property values.
+   */
+  public function toArray();
+
+  /**
+   * Determines whether the data structure is empty.
+   *
+   * @return boolean
+   *   TRUE if the data structure is empty, FALSE otherwise.
+   */
+  public function isEmpty();
+}
diff --git a/core/lib/Drupal/Core/TypedData/StructureTranslatableInterface.php b/core/lib/Drupal/Core/TypedData/StructureTranslatableInterface.php
new file mode 100644
index 0000000..74f5566
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/StructureTranslatableInterface.php
@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\StructureTranslatableInterface.
+ */
+
+namespace Drupal\Core\TypedData;
+
+/**
+ * Interface for translatable data structures.
+ */
+interface StructureTranslatableInterface extends StructureInterface {
+
+  /**
+   * Returns the default language.
+   *
+   * @return
+   *   The language object.
+   */
+  public function language();
+
+  /**
+   * Returns the languages the data is translated to.
+   *
+   * @param bool $include_default
+   *   Whether the default language should be included.
+   *
+   * @return
+   *   An array of language objects, keyed by language codes.
+   */
+  public function getTranslationLanguages($include_default = TRUE);
+
+  /**
+   * Gets a translation of contained properties.
+   *
+   * @param $langcode
+   *   The language code of the translation to get or LANGUAGE_DEFAULT to get
+   *   the data in default language.
+   *
+   * @return \Drupal\Core\TypedData\StructureInterface
+   *   A data structure containing the translated properties.
+   */
+  public function getTranslation($langcode);
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Binary.php b/core/lib/Drupal/Core/TypedData/Type/Binary.php
new file mode 100644
index 0000000..12e3962
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Binary.php
@@ -0,0 +1,81 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Binary.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+use InvalidArgumentException;
+
+/**
+ * The binary data type.
+ *
+ * The plain value of binary data is a PHP resource, see
+ * http://php.net/manual/en/language.types.resource.php. For setting the value
+ * a PHP resource or a (absolute) stream resource URI may be passed.
+ */
+class Binary extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The resource URI.
+   *
+   * @var string
+   */
+  protected $uri;
+
+  /**
+   * A generic resource handle.
+   *
+   * @var resource
+   */
+  public $handle = NULL;
+
+  /**
+   * Implements WrapperInterface::getValue().
+   */
+  public function getValue() {
+    if (!isset($this->handle) && isset($this->uri)) {
+      $this->handle = fopen($this->uri, 'rb');
+    }
+    return $this->handle;
+  }
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    if (!isset($value)) {
+      $this->handle = NULL;
+      $this->uri = NULL;
+    }
+    elseif (is_resource($value)) {
+      $this->handle = $value;
+    }
+    elseif (is_string($value)) {
+      $this->uri = $value;
+    }
+    else {
+      throw new InvalidArgumentException("Invalid value for binary data given.");
+    }
+  }
+
+  /**
+   * Implements WrapperInterface::getString().
+   */
+  public function getString() {
+    $contents = '';
+    while (!feof($this->getValue())) {
+      $contents .= fread($this->handle, 8192);
+    }
+    return $contents;
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Boolean.php b/core/lib/Drupal/Core/TypedData/Type/Boolean.php
new file mode 100644
index 0000000..de67e06
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Boolean.php
@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Boolean.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+
+/**
+ * The boolean data type.
+ *
+ * The plain value of a boolean is a regular PHP boolean. For setting the value
+ * any PHP variable that casts to a boolean may be passed.
+ */
+class Boolean extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var boolean
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    $this->value = isset($value) ? (bool) $value : $value;
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Date.php b/core/lib/Drupal/Core/TypedData/Type/Date.php
new file mode 100644
index 0000000..a60c20d
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Date.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Date.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+use DateTime;
+use InvalidArgumentException;
+
+/**
+ * The date data type.
+ *
+ * The plain value of a date is an instance of the DateTime class. For setting
+ * the value an instance of the DateTime class, any string supported by
+ * DateTime::__construct(), or a timestamp as integer may be passed.
+ */
+class Date extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var DateTime
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::getValue().
+   */
+  public function getValue() {
+    return $this->value;
+  }
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    if ($value instanceof DateTime || !isset($value)) {
+      $this->value = $value;
+    }
+    elseif (is_numeric($value)) {
+      // Value is a timestamp.
+      $this->value = new DateTime('@' . $value);
+    }
+    elseif (is_string($value)) {
+      $this->value = new DateTime($value);
+    }
+    else {
+      throw new InvalidArgumentException("Invalid date format given.");
+    }
+  }
+
+  /**
+   * Implements WrapperInterface::getString().
+   */
+  public function getString() {
+    return (string) $this->getValue()->format(DateTime::ISO8601);
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Decimal.php b/core/lib/Drupal/Core/TypedData/Type/Decimal.php
new file mode 100644
index 0000000..3bede7e
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Decimal.php
@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Decimal.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+
+/**
+ * The decimal data type.
+ *
+ * The plain value of a decimal is a regular PHP float. For setting the value
+ * any PHP variable that casts to a float may be passed.
+ */
+class Decimal extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var float
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    $this->value = isset($value) ? (float) $value : $value;
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Duration.php b/core/lib/Drupal/Core/TypedData/Type/Duration.php
new file mode 100644
index 0000000..5dc8fc9
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Duration.php
@@ -0,0 +1,66 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Duration.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+use DateInterval;
+use InvalidArgumentException;
+
+/**
+ * The duration data type.
+ *
+ * The plain value of a duration is an instance of the DateInterval class. For
+ * setting the value an instance of the DateInterval class, a ISO8601 string as
+ * supported by DateInterval::__construct, or an integer in seconds may be
+ * passed.
+ */
+class Duration extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var \DateInterval
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    if ($value instanceof DateInterval || !isset($value)) {
+      $this->value = $value;
+    }
+    elseif (is_numeric($value)) {
+      // Value is a time span in seconds.
+      $this->value = new DateInterval('PT' . $value . 'S');
+    }
+    elseif (is_string($value)) {
+      // @todo: Add support for negative intervals on top of the DateInterval
+      // constructor.
+      $this->value = new DateInterval($value);
+    }
+    else {
+      throw new InvalidArgumentException("Invalid duration format given.");
+    }
+  }
+
+  /**
+   * Implements WrapperInterface::getString().
+   */
+  public function getString() {
+    // Generate an ISO 8601 formatted string as supported by
+    // DateInterval::__construct() and setValue().
+    return (string) $this->getValue()->format('%rP%yY%mM%dDT%hH%mM%sS');
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Integer.php b/core/lib/Drupal/Core/TypedData/Type/Integer.php
new file mode 100644
index 0000000..1d6bf3f
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Integer.php
@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Integer.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+
+/**
+ * The integer data type.
+ *
+ * The plain value of an integer is a regular PHP integer. For setting the value
+ * any PHP variable that casts to an integer may be passed.
+ */
+class Integer extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var integer
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    $this->value = isset($value) ? (int) $value : $value;
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Language.php b/core/lib/Drupal/Core/TypedData/Type/Language.php
new file mode 100644
index 0000000..068a32e
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Language.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Language.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+use InvalidArgumentException;
+
+/**
+ * Defines the 'language' data type, e.g. the computed 'language' property of language items.
+ *
+ * The plain value of a language is the language object, i.e. an instance of
+ * Drupal\Core\Language\Language. For setting the value the language object or
+ * the language code as string may be passed.
+ *
+ * Supported settings (below the definition's 'settings' key) are:
+ *  - langcode source: If used as computed property, the langcode property used
+ *    to load the language object.
+ */
+class Language extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data wrapper holding the langcode value.
+   *
+   * @var \Drupal\Core\TypedData\WrapperInterface
+   */
+  protected $langcode;
+
+  /**
+   * Implements WrapperInterface::__construct().
+   */
+  public function __construct(array $definition, $value = NULL, array $context = array()) {
+    $this->definition = $definition;
+
+    if (isset($context['parent']) && !empty($this->definition['settings']['langcode source'])) {
+      $this->langcode = $context['parent']->get($this->definition['settings']['langcode source']);
+    }
+    else {
+      // No context given, so just initialize an langcode property for storing
+      // the code.
+      $this->langcode = drupal_wrap_data(array('type' => 'string'));
+    }
+
+    if (isset($value)) {
+      $this->setValue($value);
+    }
+  }
+
+  /**
+   * Implements WrapperInterface::getValue().
+   */
+  public function getValue() {
+    $langcode = $this->langcode->getValue();
+    return $langcode ? language_load($langcode) : NULL;
+  }
+
+  /**
+   * Implements WrapperInterface::setValue().
+   *
+   * Both the langcode and the language object may be passed as value.
+   */
+  public function setValue($value) {
+    if (!isset($value)) {
+      $this->langcode->setValue(NULL);
+    }
+    elseif (is_scalar($value)) {
+      $this->langcode->setValue($value);
+    }
+    elseif (is_object($value)) {
+      $this->langcode->setValue($value->langcode);
+    }
+    else {
+      throw new InvalidArgumentException('Value is no valid langcode or language object.');
+    }
+  }
+
+  /**
+   * Implements WrapperInterface::getString().
+   */
+  public function getString() {
+    $language = $this->getValue();
+    return $language ? $language->name : '';
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/String.php b/core/lib/Drupal/Core/TypedData/Type/String.php
new file mode 100644
index 0000000..2adce82
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/String.php
@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\String.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+
+/**
+ * The string data type.
+ *
+ * The plain value of a string is a regular PHP string. For setting the value
+ * any PHP variable that casts to a string may be passed.
+ */
+class String extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var string
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    $this->value = isset($value) ? (string) $value : $value;
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/Uri.php b/core/lib/Drupal/Core/TypedData/Type/Uri.php
new file mode 100644
index 0000000..9b933ea
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/Uri.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\Uri.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+
+/**
+ * The URI data type.
+ *
+ * The plain value of a URI is an absolute URI represented as PHP string.
+ */
+class Uri extends WrapperBase implements WrapperInterface {
+
+  /**
+   * The data value.
+   *
+   * @var string
+   */
+  protected $value;
+
+  /**
+   * Implements WrapperInterface::setValue().
+   */
+  public function setValue($value) {
+    $this->value = isset($value) ? (string) $value : $value;
+  }
+
+  /**
+   * Implements WrapperInterface::validate().
+   */
+  public function validate() {
+    // TODO: Implement validate() method.
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/Type/WrapperBase.php b/core/lib/Drupal/Core/TypedData/Type/WrapperBase.php
new file mode 100644
index 0000000..6411cb6
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/Type/WrapperBase.php
@@ -0,0 +1,86 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\Type\WrapperBase.
+ */
+
+namespace Drupal\Core\TypedData\Type;
+use Drupal\Core\TypedData\WrapperInterface;
+
+/**
+ * The abstract base class for data types.
+ *
+ * Classes deriving from this base class have to declare $value
+ * or override getValue() or setValue().
+ */
+abstract class WrapperBase implements WrapperInterface {
+
+  /**
+   * The data definition.
+   *
+   * @var array
+   */
+  protected $definition;
+
+  /**
+   * Implements WrapperInterface::__construct().
+   *
+   * @param array $definition
+   *
+   * @param mixed $value;
+   *
+   * @param array $context;
+   */
+  public function __construct(array $definition, $value = NULL, array $context = array()) {
+    $this->definition = $definition;
+    if (isset($value)) {
+      $this->setValue($value);
+    }
+  }
+
+  /**
+   * Implements WrapperInterface::getType().
+   *
+   * @return string
+   */
+  public function getType() {
+    return $this->definition['type'];
+  }
+
+  /**
+   * Implements WrapperInterface::getDefinition().
+   *
+   * @return array
+   */
+  public function getDefinition() {
+    return $this->definition;
+  }
+
+  /**
+   * Implements WrapperInterface::getValue().
+   *
+   * @return mixed
+   */
+  public function getValue() {
+    return $this->value;
+  }
+
+  /**
+   * Implements WrapperInterface::setValue().
+   *
+   * @param mixed $value
+   */
+  public function setValue($value) {
+    $this->value = $value;
+  }
+
+  /**
+   * Implements WrapperInterface::getString().
+   *
+   * @return string
+   */
+  public function getString() {
+    return (string) $this->getValue();
+  }
+}
diff --git a/core/lib/Drupal/Core/TypedData/WrapperInterface.php b/core/lib/Drupal/Core/TypedData/WrapperInterface.php
new file mode 100644
index 0000000..75acaf5
--- /dev/null
+++ b/core/lib/Drupal/Core/TypedData/WrapperInterface.php
@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\TypedData\WrapperInterface.
+ */
+
+namespace Drupal\Core\TypedData;
+use Drupal\user;
+
+/**
+ * Interface for typed data wrappers.
+ */
+interface WrapperInterface {
+
+  /**
+   * Creates a wrapper object given its definition and value.
+   *
+   * @param array $definition
+   *   The data definition.
+   * @param mixed $value
+   *   (optional) The data value, or NULL if the it is not set. See
+   *   WrapperInterface::setValue() for details.
+   * @param array $context
+   *   (optional) An array describing the context of the data. It should be
+   *   passed if a data value is wrapped as part of a data structure. The
+   *   following keys are supported:
+   *   - name: The name of the data being wrapped.
+   *   - parent: The parent object containing the data. Must be an instance of
+   *     \Drupal\Core\TypedData\StructureInterface.
+   *
+   * @see drupal_wrap_data()
+   */
+  public function __construct(array $definition, $value = NULL, array $context = array());
+
+  /**
+   * Gets the data type.
+   *
+   * @return string
+   *   The data type of the wrapped data.
+   */
+  public function getType();
+
+  /**
+   * Gets the data definition.
+   *
+   * @return array
+   *   The data definition array.
+   */
+  public function getDefinition();
+
+  /**
+   * Gets the data value.
+   *
+   * @return mixed
+   */
+  public function getValue();
+
+  /**
+   * Sets the data value.
+   *
+   * @param mixed $value
+   *   The value to set in the format as documented for the data type or NULL to
+   *   unset the data value.
+   *
+   * @throws \Drupal\Core\TypedData\ReadOnlyException
+   *   If the data is read-only.
+   */
+  public function setValue($value);
+
+  /**
+   * Returns a string representation of the data.
+   *
+   * @return string
+   */
+  public function getString();
+
+  /**
+   * Validates the currently set data value.
+   */
+  public function validate();
+
+}
diff --git a/core/modules/system/lib/Drupal/system/Tests/TypedData/DataWrapperTest.php b/core/modules/system/lib/Drupal/system/Tests/TypedData/DataWrapperTest.php
new file mode 100644
index 0000000..23dd238
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/TypedData/DataWrapperTest.php
@@ -0,0 +1,130 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\system\Tests\TypedData\DataWrapperTest.
+ */
+
+namespace Drupal\system\Tests\TypedData;
+
+use Drupal\simpletest\WebTestBase;
+use DateTime;
+use DateInterval;
+
+/**
+ * Tests primitive data types.
+ */
+class DataWrapperTest extends WebTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Test data wrappers',
+      'description' => 'Tests the functionality of all core data wrappers.',
+      'group' => 'Typed Data API',
+    );
+  }
+
+  /**
+   * Tests the basics around constructing and working with data wrappers.
+   */
+  public function testGetAndSet() {
+    // Boolean type.
+    $wrapper = $this->drupalWrapData(array('type' => 'boolean'), TRUE);
+    $this->assertTrue($wrapper->getValue() === TRUE, 'Boolean value was fetched.');
+    $wrapper->setValue(FALSE);
+    $this->assertTrue($wrapper->getValue() === FALSE, 'Boolean value was changed.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Boolean value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'Boolean wrapper is null-able.');
+
+    // String type.
+    $value = $this->randomString();
+    $wrapper = $this->drupalWrapData(array('type' => 'string'), $value);
+    $this->assertTrue($wrapper->getValue() === $value, 'String value was fetched.');
+    $new_value = $this->randomString();
+    $wrapper->setValue($new_value);
+    $this->assertTrue($wrapper->getValue() === $new_value, 'String value was changed.');
+    // Funky test.
+    $this->assertTrue(is_string($wrapper->getString()), 'String value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'String wrapper is null-able.');
+
+    // Integer type.
+    $value = rand();
+    $wrapper = $this->drupalWrapData(array('type' => 'integer'), $value);
+    $this->assertTrue($wrapper->getValue() === $value, 'Integer value was fetched.');
+    $new_value = rand();
+    $wrapper->setValue($new_value);
+    $this->assertTrue($wrapper->getValue() === $new_value, 'Integer value was changed.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Integer value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'Integer wrapper is null-able.');
+
+    // Decimal type.
+    $value = 123.45;
+    $wrapper = $this->drupalWrapData(array('type' => 'decimal'), $value);
+    $this->assertTrue($wrapper->getValue() === $value, 'Decimal value was fetched.');
+    $new_value = 678.90;
+    $wrapper->setValue($new_value);
+    $this->assertTrue($wrapper->getValue() === $new_value, 'Decimal value was changed.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Decimal value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'Decimal wrapper is null-able.');
+
+    // Date type.
+    $value = new DateTime('@' . REQUEST_TIME);
+    $wrapper = $this->drupalWrapData(array('type' => 'date'), $value);
+    $this->assertTrue($wrapper->getValue() === $value, 'Date value was fetched.');
+    $new_value = REQUEST_TIME + 1;
+    $wrapper->setValue($new_value);
+    $this->assertTrue($wrapper->getValue()->getTimestamp() === $new_value, 'Date value was changed and set by timestamp.');
+    $wrapper->setValue('2000-01-01');
+    $this->assertTrue($wrapper->getValue()->format('Y-m-d') == '2000-01-01', 'Date value was changed and set by date string.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Date value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'Date wrapper is null-able.');
+
+    // Duration type.
+    $value = new DateInterval('PT20S');
+    $wrapper = $this->drupalWrapData(array('type' => 'duration'), $value);
+    $this->assertTrue($wrapper->getValue() === $value, 'Duration value was fetched.');
+    $wrapper->setValue(10);
+    $this->assertTrue($wrapper->getValue()->s == 10, 'Duration value was changed and set by time span in seconds.');
+    $wrapper->setValue('P40D');
+    $this->assertTrue($wrapper->getValue()->d == 40, 'Duration value was changed and set by duration string.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Duration value was converted to string');
+    // Test getting the string and passing it back as value.
+    $duration = $wrapper->getString();
+    $wrapper->setValue($duration);
+    $this->assertEqual($wrapper->getString(), $duration, 'Duration formatted as string can be used to set the duration value.');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'Duration wrapper is null-able.');
+
+    // Generate some files that will be used to test the URI and the binary
+    // data types.
+    $files = $this->drupalGetTestFiles('image');
+
+    // URI type.
+    $wrapper = $this->drupalWrapData(array('type' => 'uri'), $files[0]->uri);
+    $this->assertTrue($wrapper->getValue() === $files[0]->uri, 'URI value was fetched.');
+    $wrapper->setValue($files[1]->uri);
+    $this->assertTrue($wrapper->getValue() === $files[1]->uri, 'URI value was changed.');
+    $this->assertTrue(is_string($wrapper->getString()), 'URI value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'URI wrapper is null-able.');
+
+    // Binary type.
+    $wrapper = $this->drupalWrapData(array('type' => 'binary'), $files[0]->uri);
+    $this->assertTrue(is_resource($wrapper->getValue()), 'Binary value was fetched.');
+    // Try setting by URI.
+    $wrapper->setValue($files[1]->uri);
+    $this->assertEqual(is_resource($wrapper->getValue()), fopen($files[1]->uri, 'r'), 'Binary value was changed.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Binary value was converted to string');
+    // Try setting by resource.
+    $wrapper->setValue(fopen($files[2]->uri, 'r'));
+    $this->assertEqual(is_resource($wrapper->getValue()), fopen($files[2]->uri, 'r'), 'Binary value was changed.');
+    $this->assertTrue(is_string($wrapper->getString()), 'Binary value was converted to string');
+    $wrapper->setValue(NULL);
+    $this->assertNull($wrapper->getValue(), 'Binary wrapper is null-able.');
+  }
+}