POI Spreadsheet Manager - Part 1

I've been working on this project for about two years off and on now. Some parts of it shaped up early on, while others have undergone significant refactoring. Most of my reports are in Excel, but some few are done in Word. So I started with a class that accepts any POI XML document and a file name, and sends that file to the browser.


This is pretty straightforward, but is the black magic behind delivering the actual spreadsheet through the browser.

package itd.poi;

import itd.extlib.utils.jsf.JSFUtils;

import java.io.OutputStream;
import java.io.Serializable;

import javax.faces.context.FacesContext;

import org.apache.poi.POIXMLDocument;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.xwpf.usermodel.XWPFDocument;

import com.ibm.xsp.webapp.XspHttpServletResponse;

/*
 * This is a bridge between an XAgent and a PoiXmlDocument. It handles writing
 * the document back to the browser.
 */
public abstract class PoiBase implements Serializable {
    protected static final long serialVersionUID = 1L;

    protected static void write(POIXMLDocument poiXmlDoc, String filename) {
        // Create variables
        FacesContext facesContext = FacesContext.getCurrentInstance();
        XspHttpServletResponse response = JSFUtils.getResponse();
        OutputStream pageOut = null;

        try {
            pageOut = response.getOutputStream();
            if (poiXmlDoc instanceof XWPFDocument) {
                response.setContentType("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
            } else if (poiXmlDoc instanceof XSSFWorkbook) {
                response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            }
            response.setHeader("Cache-Control", "no-cache");
            response.setHeader("Content-Disposition", "attachment; filename=" + filename);

            poiXmlDoc.write(pageOut);
            pageOut.flush();
            pageOut.close();
        } catch (Exception e) {
            throw new RuntimeException("Error generating dynamic XML document: " + e.getMessage());
        } finally {
            facesContext.responseComplete();
        }
    }
}