code: public FilterFunction composite(final String name,
                                      final Optional<String> content)
      {
          return compositeCache.apply(name).map(constraint -> composite(constraint,
                                                                        content))
                               .orElseThrow(() -> new IllegalStateException(String.format("No constraint with name [%s] found",
                                                                                          name)));
      }
docs: A constraint that uses a {@link Constraint} to determine access.  This may be an arbitrarily complex
  tree of constraints.
  
  @param name    the name of the composite constraint defined in {@link CompositeCache}.
  @param content is passed to {@link DeadboltHandler#onAuthFailure(Http.RequestHeader, Optional)} if the authorization fails
  @return a function that wraps the constraint
  @throws IllegalStateException if no constraint with the given name is present in the composite cache