reading after parse exception

Hi,
 I have a situation where I need to be able to read the rest of the input
stream after a parse exception has been thrown. I am able  to access the
java.io.Reader from the parser by declaring:
                                  Reader reader =
token_source.input_stream.inputStream;

But the reader appears to be invalid or closed. the next character read
returns  (-1).

Is there any way I can pinpoint the part of the input stream ( in my case a
String) where the parseException was thrown.

    thanks

        Anil