protected  void addFooter(OutputStream theOutputStream) throws IOException 
{
        String footer = this.config.getInitParameter("footer");
        if (footer != null)
        {
            theOutputStream.write(footer.getBytes());
        }
}

Write the footer to the output stream. The footer text is extracted from a filter initialisation parameter (defined in web.xml). Don't write anything if no parameter is defined.

 protected  void addHeader(OutputStream theOutputStream) throws IOException 
{
        String header = this.config.getInitParameter("header");
        if (header != null)
        {
            theOutputStream.write(header.getBytes());
        }
}

Write the header to the output stream. The header text is extracted from a filter initialisation parameter (defined in web.xml). Don't write anything if no parameter is defined.

 public  void destroy() 
{

}

Filter un-initialisation. Called by the servlet engine during the life cycle of the filter.

 public  void doFilter(ServletRequest theRequest,
    ServletResponse theResponse,
    FilterChain theChain) throws IOException, ServletException 
{
        OutputStream out = theResponse.getOutputStream();
        addHeader(out);
        // Create a wrapper of the response so that we can later write to
        // the response (add the footer). If we did not do this, we would
        // get an error saying that the response has already been
        // committed.
        GenericResponseWrapper wrapper = 
            new GenericResponseWrapper((HttpServletResponse) theResponse);
        theChain.doFilter(theRequest, wrapper);
        out.write(wrapper.getData());
        addFooter(out);
        out.close();
}

Perform the filter function. Called by the container upon a request matching the filter pattern defined in web.xml.

 public  void init(FilterConfig theConfig) throws ServletException 
{
        this.config = theConfig;
}

Filter initialisation. Called by the servlet engine during the life cycle of the filter.