public PageResponseWrapper(HttpServletResponse response,
    Factory factory) 
{
        super(response);
        this.factory = factory;
        routablePrintWriter = new RoutablePrintWriter(new RoutablePrintWriter.DestinationFactory() {
            public PrintWriter activateDestination() throws IOException {
                return response.getWriter();
            }
        });
        routableServletOutputStream = new RoutableServletOutputStream(new RoutableServletOutputStream.DestinationFactory() {
            public ServletOutputStream create() throws IOException {
                return response.getOutputStream();
            }
        });
}

 public  void addHeader(String name,
    String value) 
{
        if (name.toLowerCase().equals("content-type")) { // ensure ContentType is always set through setContentType()
            setContentType(value);
        } else if (!parseablePage || !name.toLowerCase().equals("content-length")) {
            super.addHeader(name, value);
        }
}

Prevent content-length being set if page is parseable.

 public ServletOutputStream getOutputStream() 
{
        return routableServletOutputStream;
}

 public Page getPage() throws IOException 
{
        if (aborted || !parseablePage) {
            return null;
        } else {
            return buffer.parse();
        }
}

 public PrintWriter getWriter() 
{
        return routablePrintWriter;
}

 public boolean isUsingStream() 
{
        return buffer != null && buffer.isUsingStream();
}

 public  void sendError(int sc) throws IOException 
{
        aborted = true;
        super.sendError(sc);
}

 public  void sendError(int sc,
    String msg) throws IOException 
{
        aborted = true;
        super.sendError(sc, msg);
}

 public  void sendRedirect(String location) throws IOException 
{
        aborted = true;
        super.sendRedirect(location);
}

 public  void setContentLength(int contentLength) 
{
        if (!parseablePage) super.setContentLength(contentLength);
}

Prevent content-length being set if page is parseable.

 public  void setContentType(String type) 
{
        super.setContentType(type);
        if (type != null) {
            // this is the content type + charset. eg: text/html;charset=UTF-8
            int offset = type.lastIndexOf("charset=");
            String encoding = null;
            if (offset != -1)
               encoding = extractContentTypeValue(type, offset + 8);
            String contentType = extractContentTypeValue(type, 0);
            if (factory.shouldParsePage(contentType)) {
                activateSiteMesh(contentType, encoding);
            }
        }
}

Set the content-type of the request and store it so it can be passed to the com.opensymphony.module.sitemesh.PageParser .

 public  void setHeader(String name,
    String value) 
{
        if (name.toLowerCase().equals("content-type")) { // ensure ContentType is always set through setContentType()
            setContentType(value);
        } else if (!parseablePage || !name.toLowerCase().equals("content-length")) {
            super.setHeader(name, value);
        }
}

Prevent content-length being set if page is parseable.

 public  void setStatus(int sc) 
{
        if (!parseablePage || sc != HttpServletResponse.SC_NOT_MODIFIED) {
            super.setStatus(sc);
        }
}

Prevent 'not modified' (304) HTTP status from being sent if page is parseable (so web-server/browser doesn't cache contents).