code: public boolean functionAvailable(String ns, String funcName)
            throws javax.xml.transform.TransformerException
    {
      boolean isAvailable = false;
      
      if (null != ns)
      {
        ExtensionHandler extNS = 
             (ExtensionHandler) m_extensionFunctionNamespaces.get(ns);
        if (extNS != null)
          isAvailable = extNS.isFunctionAvailable(funcName);
      }
      return isAvailable;
    }
docs: Execute the function-available() function.
  @param ns       the URI of namespace in which the function is needed
  @param funcName the function name being tested
  
  @return whether the given function is available or not.
  
  @throws javax.xml.transform.TransformerException