ValueJXPathBindingBuilder provides a helper class for the Factory
implemented in
JXPathBindingManager that helps construct the
actual
ValueJXPathBinding out of the configuration in the
provided configElement which looks like:
<fb:value id="widget-id" path="xpath-expression">
<!-- optional child binding to be executed upon 'save' of changed value -->
<fb:on-update>
<!-- any childbinding -->
</fb:on-update>
</fb:value>