dinamica.AbstractPDFOutput.java Source code

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Here is the source code for dinamica.AbstractPDFOutput.java

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package dinamica;

import javax.servlet.*;
import java.io.ByteArrayOutputStream;
import com.lowagie.text.*;
import com.lowagie.text.pdf.*;

/**
 * Base class to produce PDF output modules (hand made reports)
 * based on the powerful IText-PDF open source component.<br>
 * This super class provides several common utility methods, including
 * the abiity to auto-read the report header, footer and title from web.xml
 * or config.xml, and to retrieve images from URLs (local or remotes), which is
 * used to insert charts into the PDF document by reusing a server-side chart Action, 
 * or to insert another dinamically generated image, like a BarCode. The method to retrieve
 * via HTTP is session sensitive, meaning that it can reuse the same session ID, which is
 * a requirement when accessing local resources that are session-sensitive, like chart Actions.
 * <br><br>
 * In order to reuse this class, you must override the method createPDF(), you may use
 * the default implementation as a code template. For more information look into
 * the /source and /templates resources included with Dinamica distribution.
 * <br><br>
 * (c) 2004 Martin Cordova<br>
 * This code is released under the LGPL license<br>
 * Dinamica Framework - http://www.martincordova.com
 * @author Martin Cordova (dinamica@martincordova.com)
 * */
public class AbstractPDFOutput extends GenericOutput {

    /* (non-Javadoc)
     * @see dinamica.GenericOutput#print(dinamica.GenericTransaction)
     */
    public void print(GenericTransaction data) throws Throwable {
        ByteArrayOutputStream buf = new ByteArrayOutputStream(32768);
        createPDF(data, buf);
        getResponse().setContentType("application/pdf");
        getResponse().setContentLength(buf.size());
        ServletOutputStream out = getResponse().getOutputStream();
        buf.writeTo(out);
        out.close();
    }

    /**
     * Receives a byte buffer that should be filled with resulting PDF.
     * @param data Data module that provides recordsets to this output module
     * @param buf Buffer to print PDF, then used to send to browser
     * @throws Throwable
     */
    protected void createPDF(GenericTransaction data, ByteArrayOutputStream buf) throws Throwable {

        //pdf objects
        Document doc = new Document();
        PdfWriter docWriter = PdfWriter.getInstance(doc, buf);

        //header
        HeaderFooter header = new HeaderFooter(new Phrase(getHeader()), false);
        header.setBorder(Rectangle.BOTTOM);
        header.setAlignment(Rectangle.ALIGN_CENTER);
        doc.setHeader(header);

        //footer
        HeaderFooter footer = new HeaderFooter(new Phrase(getFooter()), true);
        footer.setBorder(Rectangle.TOP);
        footer.setAlignment(Rectangle.ALIGN_RIGHT);
        doc.setFooter(footer);

        //pagesize
        doc.setPageSize(PageSize.LETTER);

        doc.open();

        //title
        Paragraph t = new Paragraph(getReportTitle(), new Font(Font.HELVETICA, 18f));
        t.setAlignment(Rectangle.ALIGN_CENTER);
        doc.add(t);

        //paragraph
        Paragraph p = new Paragraph("Hello World");
        p.setAlignment(Rectangle.ALIGN_CENTER);
        doc.add(p);

        doc.close();
        docWriter.close();

    }

    /**
     * Calcula si una tabla (mas un espacio extra) cabe en lo que queda de pagina.
     * Este metodo compensa la desaparicion del metodo fitsPage que IText tenia
     * hasta la version 2.0.6, y es necesario en reportes tipo master/detail o parent/child,
     * fue necesario crear este metodo para poder usar el ultimo IText (v2.1.2).
     * @param doc Document ya inicializado
     * @param docWriter PdfWriter ya inicializado
     * @param tbl La tabla, su ancho debe haber sido definido con setTotalWidth, es decir usando
     * un ancho absoluto, no porcentajes, de otro modo este metodo no hara un calculo correcto, por
     * una limitacion de IText.
     * @param extra Espacio extra para el calculo si se desea, sino pase cero.
     * @return
     */
    protected boolean fitsPage(Document doc, PdfWriter docWriter, PdfPTable tbl, int extra) {

        float a = tbl.getTotalHeight() + extra;
        float b = doc.bottom(doc.bottomMargin());
        float c = docWriter.getVerticalPosition(true);

        return ((c - b) > a);

    }

    /**
     * Get default report header (parameter pdf-header) from web.xml (context-param) or current config.xml (custom element).
     * Any subclass may override this method.
     * @return Report header text or NULL
     */
    protected String getHeader() {

        return getPDFConfigValue("pdf-header");

    }

    /**
     * Get default report footer (parameter pdf-footer) from web.xml (context-param) or current config.xml (custom element).
     * Any subclass may override this method.
     * @return Report footer text or NULL
     */
    protected String getFooter() {
        return getPDFConfigValue("pdf-footer") + " ";
    }

    /**
     * Get default report title (parameter pdf-title) from web.xml (context-param) or current config.xml (custom element).
     * Most of the time the report title should be defined in config.xml because it is
     * specific to the report.
     * Any subclass may override this method.
     * @return Report title text or NULL
     */
    protected String getReportTitle() {
        return getPDFConfigValue("pdf-title");
    }

    /**
     * Read a PDF-related config parameter. Will search first
     * in the Action config.xml, then in web.xml file.
     * @param param
     * @return The corresponding value or NULL if not found.
     */
    protected String getPDFConfigValue(String param) {
        String value = null;
        try {
            value = getConfig().getConfigValue(param);
            if (value == null || value.trim().equals("")) {
                value = getContext().getInitParameter(param);
            }
        } catch (Throwable e) {
            value = getContext().getInitParameter(param);
            if (value == null)
                value = "";
        }
        return value;
    }

}