package com.kiasoft.modules.screens.pdf;

/* ------------------------------------------------------------------
 * Kiasoft, Inc.
 * http://kiasoft.com
 *
 * Copyright (c) 2004-2006 Kiasoft, Inc. All Rights Reserved.
 *
 * ------------------------------------------------------------------ */


import java.io.ByteArrayOutputStream;

import org.apache.turbine.modules.screens.RawScreen;
import org.apache.turbine.util.RunData;

/**
 * RawScreen for displaying generated PDF files
 */
public abstract class PdfScreen extends RawScreen
{

   /**
    * Set the content type to Pdf. (see RawScreen)
    *
    * @param data Turbine information.
    * @return content type.
    */
    public String getContentType(RunData data)
    {
        return "application/pdf";
    };

    /**
    * Classes that implement this ADT must override this to build the pdf
    * file.
    * @param data RunData
    * @return ByteArrayOutputStream
    * @exception Exception, any old exception.
    */
    protected abstract ByteArrayOutputStream buildPdf (RunData data) 
	throws Exception;

    /**
    * Overrides & finalizes doOutput in RawScreen to serve the output stream
    * created in buildPDF.
    *
    * @param data RunData
    * @exception Exception, any old generic exception.
    */
    protected final void doOutput(RunData data) throws Exception
    {

        ByteArrayOutputStream baos = buildPdf(data);
        if (baos != null)
        {
            javax.servlet.http.HttpServletResponse response = data.getResponse();
            //We have to set the size to workaround a bug in IE (see com.lowagie iText FAQ)
            data.getResponse().setContentLength(baos.size());
            javax.servlet.ServletOutputStream out = response.getOutputStream();
            baos.writeTo(out);
        }
        else
        {
            throw new Exception("output stream from buildPDF is null");
        }
    }

}