code: public void compose(StylesheetRoot sroot) throws TransformerException
    {
      super.compose(sroot);
      m_extns = this.getNamespace();   
      m_decl = getElemExtensionDecl(sroot, m_extns);
      // Register the extension namespace if the extension does not have
      // an ElemExtensionDecl ("component").
      if (m_decl == null)
        sroot.getExtensionNamespacesManager().registerExtension(m_extns);
    }
docs: This function is called after everything else has been
  recomposed, and allows the template to set remaining
  values that may be based on some other property that
  depends on recomposition.