code: @Override
      public void encodeAll(FacesContext context) throws IOException {
          if (context == null) {
              throw new NullPointerException();
          }
  
          // if there is a value expression, update view parameter w/ latest value after render
          // QUESTION is it okay that a null string value may be suppressing the view parameter value?
          // ANSWER: I'm not sure.
          setSubmittedValue(getStringValue(context));
      }
docs: <p class="changed_added_2_0">Called specially by {@link
  UIViewRoot#encodeEnd}, this method simply sets the submitted
  value to be the return from {@link #getStringValue}.</p>
  @since 2.0