=doc,htp #18657 document FormField vals

akka-docs-dev/rst/java/http/routing-dsl/request-vals/form-field-request-vals.rst

@@ -0,0 +1,33 @@
+.. _form-field-request-vals-java:
+
+Request Values: FormFields
+==========================
+
+A collection of pre-defined :ref:`request-vals-java` that can be used to extract header values from incoming requests.
+
+Description
+-----------
+Header request values allow extracting ``HttpHeader`` values or concrete instances from HTTP requests.
+
+The ``RequestVal`` builder is made up of 2 steps, initially you need to pick which Header to extract (``byName`` or
+``byClass``) and then you need to pick if the header is optionally available or required (i.e. the route should not
+match if the header is not present in the request). This is done using one of the below depicted methods::
+
+  RequestVal<T> instance()
+  RequestVal<<Option<T>> optionalInstance()
+
+  RequestVal<String> value()
+  RequestVal<Option<String>> optionalValue()
+
+Examples
+--------
+
+``Headers.byClass(Class[HttpHeader])``
+
+.. includecode:: ../../../code/docs/http/javadsl/server/HeaderRequestValsExampleTest.java
+   :include: by-class
+
+``Headers.byName(String)``
+
+.. includecode:: ../../../code/docs/http/javadsl/server/HeaderRequestValsExampleTest.java
+   :include: by-name

akka-docs-dev/rst/java/http/routing-dsl/request-vals/index.rst

@@ -27,7 +27,7 @@ service.
 
 These request values are defined in the following objects:
 
-akka.http.javadsl.server.values.FormFieldsRequestVals
+:ref:`akka.http.javadsl.server.values.FormFields <form-field-request-vals-java>`
   Contains request values for basic data like URI components, request method, peer address, or the entity data.
 akka.http.javadsl.server.values.FormFieldsCookies
   Contains request values representing cookies.