public void registerExtension(ExtensionNamespaceSupport extNsSpt){
  String namespace=extNsSpt.getNamespace();
  if (namespaceIndex(namespace,m_extensions) == -1) {
    m_extensions.add(extNsSpt);
    if (m_unregisteredExtensions.contains(namespace))     m_unregisteredExtensions.remove(namespace);
  }
}

public void registerExtension ( ExtensionNamespaceSupport extNsSpt ) { String namespace = extNsSpt . getNamespace ( ) ; if ( namespaceIndex ( namespace , m_extensions ) == - 1 ) { m_extensions . add ( extNsSpt ) ; if ( m_unregisteredExtensions . contains ( namespace ) ) m_unregisteredExtensions . remove ( namespace ) ; } }
register the extension namespace for an elemextensiondecl or elemfunction , and prepare a support object to launch the appropriate extensionhandler at transformation runtime .
