AbstractPdfView.java

package com.transformuk.bdt.view;

import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.view.AbstractView;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.pdf.PdfWriter;
 
/**
 * This class is a work around for working with iText 5.x in Spring.
 * i.e. it uses the package com.itextpdf.* instead of the com.lowagie.*
 */
public abstract class AbstractPdfView extends AbstractView {
 
    public AbstractPdfView() {
        setContentType("application/pdf");
    }
 
    @Override
    protected boolean generatesDownloadContent() {
        return true;
    }
         
    @Override
    protected void renderMergedOutputModel(Map<String, Object> model,
            HttpServletRequest request, HttpServletResponse response) throws Exception {
    	
        // IE workaround: write into byte array first.
        ByteArrayOutputStream baos = createTemporaryOutputStream();
 
        // Apply preferences and build metadata.
        Document document = newDocument();
        PdfWriter writer = newWriter(document, baos);
        prepareWriter(model, writer, request);
        buildPdfMetadata(model, document, request);
 
        // Build PDF document.
        document.open();
        buildPdfDocument(model, document, writer, request, response);
        document.close();
 
        // Flush to HTTP response.
        writeToResponse(response, baos);
    }
 
    protected Document newDocument() {
        return new Document(PageSize.A4);
    }
     
    protected PdfWriter newWriter(Document document, OutputStream os) throws DocumentException {
        return PdfWriter.getInstance(document, os);
    }
     
    protected void prepareWriter(Map<String, Object> model, PdfWriter writer, HttpServletRequest request)
            throws DocumentException {
 
        writer.setViewerPreferences(getViewerPreferences());
    }
     
    protected int getViewerPreferences() {
        return PdfWriter.ALLOW_PRINTING | PdfWriter.PageLayoutSinglePage;
    }
     
    protected void buildPdfMetadata(Map<String, Object> model, Document document, HttpServletRequest request) {
    }
     
    protected abstract void buildPdfDocument(Map<String, Object> model, Document document, PdfWriter writer,
            HttpServletRequest request, HttpServletResponse response) throws Exception;
}