public void addExtensionNamespace(String uri,ExtensionHandler extNS){
  m_extensionFunctionNamespaces.put(uri,extNS);
}

public void addExtensionNamespace ( String uri , ExtensionHandler extNS ) { m_extensionFunctionNamespaces . put ( uri , extNS ) ; }
register an extension namespace handler . this handler provides functions for testing whether a function is known within the namespace and also for invoking the functions .
