@@ -12,11 +12,15 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
+#import "macros.h"
+
 @class OFString;
+
+OF_ASSUME_NONNULL_BEGIN
 
 /*!
  * @protocol OFKeyValueCoding OFKeyValueCoding.h ObjFW/OFKeyValueCoding.h
  *
  * @brief A protocol for Key Value Coding.
@@ -29,11 +33,11 @@
  * @brief Return the value for the specified key
  *
  * @param key The key of the value to return
  * @return The value for the specified key
  */
-- (id)valueForKey: (OFString*)key;
+- (nullable id)valueForKey: (OFString*)key;
 
 /*!
  * @brief This is called by @ref valueForKey: if the specified key does not
  *	  exist.
  *
@@ -40,19 +44,19 @@
  * By default, this throws an @ref OFUndefinedKeyException.
  *
  * @param key The undefined key of the value to return
  * @return The value for the specified undefined key
  */
-- (id)valueForUndefinedKey: (OFString*)key;
+- (nullable id)valueForUndefinedKey: (OFString*)key;
 
 /*!
  * @brief Set the value for the specified key
  *
  * @param value The value for the specified key
  * @param key The key of the value to set
  */
-- (void)setValue: (id)value
+- (void)setValue: (nullable id)value
 	  forKey: (OFString*)key;
 
 /*!
  * @brief This is called by @ref setValue:forKey: if the specified key does not
  *	  exist.
@@ -60,8 +64,10 @@
  * By default, this throws an @ref OFUndefinedKeyException.
  *
  * @param value The value for the specified undefined key
  * @param key The undefined key of the value to set
  */
--  (void)setValue: (id)value
+-  (void)setValue: (nullable id)value
   forUndefinedKey: (OFString*)key;
 @end
+
+OF_ASSUME_NONNULL_END