dinamica.SyncChartOutput.java Source code

Introduction

Here is the source code for dinamica.SyncChartOutput.java

Source

package dinamica;

import java.awt.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.ImageIO;
import org.jfree.chart.*;

/**
 * <b>NOTA:</b> Version con acceso sincronizado al recordset qye provee la data al chart.<br>
 * Si no necesita varios threads accediendo al mismo recordset en la misma sesion, entonces usa
 * la version normal dinamica.ChartOutput.<br>
 * Specific Output Plugin for server-side charting using the JFreeChart
 * LGPL component - every available chart type is also base on a plugin
 * architecture (AbstracChartPlugin).
 * <br>
 * <br>
 * Creation date: 17/11/2003<br>
 * Last Update: 17/11/2003<br>
 * (c) 2003 Martin Cordova<br>
 * This code is released under the LGPL license<br>
 * @author Martin Cordova
 * */
public class SyncChartOutput extends GenericOutput {

    /* (non-Javadoc)
     * @see dinamica.GenericOutput#print(dinamica.GenericTransaction)
     */
    public void print(GenericTransaction t) throws Throwable {

        //get chart parameters
        Recordset chartinfo = t.getRecordset("chartinfo");

        //get chart data
        String id = chartinfo.getString("data");
        Recordset data = (Recordset) getSession().getAttribute(id);
        if (data == null)
            throw new Throwable(
                    "Invalid Recordset ID:" + id + " - The session does not contain an attribute with this ID.");

        //general chart params
        Integer width = (Integer) chartinfo.getValue("width");
        Integer height = (Integer) chartinfo.getValue("height");

        //load chart plugin
        String plugin = (String) chartinfo.getValue("chart-plugin");
        AbstractChartPlugin obj = (AbstractChartPlugin) Thread.currentThread().getContextClassLoader()
                .loadClass(plugin).newInstance();

        JFreeChart chart = null;
        synchronized (data) {
            chart = obj.getChart(chartinfo, data);
        }

        //set gradient
        chart.setBackgroundPaint(getGradient());

        //set border and legend params
        chart.setBorderPaint(Color.LIGHT_GRAY);
        chart.setBorderVisible(true);
        if (chart.getLegend() != null) {
            chart.getLegend().setBorder(0.2, 0.2, 0.2, 0.2);
            chart.getLegend().setPadding(5, 5, 5, 5);
            chart.getLegend().setMargin(4, 5, 4, 4);
        }

        //render chart in memory
        BufferedImage img = chart.createBufferedImage(width.intValue(), height.intValue());
        ByteArrayOutputStream b = new ByteArrayOutputStream(32768);

        //encode as PNG
        ImageIO.write(img, "png", b);

        //send bitmap via servlet output
        byte image[] = b.toByteArray();
        getResponse().setContentType("image/png");
        getResponse().setContentLength(image.length);
        OutputStream out = getResponse().getOutputStream();
        out.write(image);
        out.close();

        //save image bytes in session attribute if requested
        if (chartinfo.containsField("session")) {
            String session = chartinfo.getString("session");
            if (session != null && session.equals("true"))
                getSession().setAttribute(chartinfo.getString("image-id"), image);
        }

    }

    /**
     * Creates a gradient (white->gray) for charts, may
     * be overrided by subclasses to provide a custom gradient
     * @return Default gradient for charts
     */
    protected GradientPaint getGradient() {
        return new GradientPaint(0, 0, Color.WHITE, 1000, 0, Color.LIGHT_GRAY);
    }
}