/**
  * Look up a prefix and get the currently-mapped Namespace URI.
  *
  * <p>This method looks up the prefix in the current context. Use the empty string ("") for the
  * default Namespace.
  *
  * @param prefix The prefix to look up.
  * @return The associated Namespace URI, or null if the prefix is undeclared in this context.
  * @see #getPrefix
  * @see #getPrefixes
  */
 public String getURI(String prefix) {
   return currentContext.getURI(prefix);
 }