org.shredzone.bullshitcharts.servlet.ChartServlet.java Source code

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Here is the source code for org.shredzone.bullshitcharts.servlet.ChartServlet.java

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/**
 * bullshitcharts - A Bullshit Chart Generator
 *
 * Copyright (C) 2009 Richard "Shred" Krber
 *   http://bullshitcharts.shredzone.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.shredzone.bullshitcharts.servlet;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

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

import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.Plot;
import org.shredzone.bullshitcharts.chart.AgreementPieGenerator;
import org.shredzone.bullshitcharts.chart.BarChartGenerator;
import org.shredzone.bullshitcharts.chart.ChoicePieGenerator;
import org.shredzone.bullshitcharts.chart.LineChartGenerator;
import org.shredzone.bullshitcharts.chart.PlotGenerator;

/**
 * Servlet that returns a random chart depending on the path name and request parameters.
 *
 * @author Richard "Shred" Krber
 */
public class ChartServlet extends HttpServlet {
    private static final long serialVersionUID = 7200291835832529046L;

    private static final int IMAGE_WIDTH = 640;
    private static final int IMAGE_HEIGHT = 480;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        String pathInfo = req.getPathInfo();
        PlotGenerator generator = null;
        if ("/pie.png".equals(pathInfo)) {
            generator = new ChoicePieGenerator();
        } else if ("/agree.png".equals(pathInfo)) {
            generator = new AgreementPieGenerator();
        } else if ("/line.png".equals(pathInfo)) {
            generator = new LineChartGenerator();
        } else if ("/bar.png".equals(pathInfo)) {
            generator = new BarChartGenerator();
        } else {
            resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        generator.configure(req);

        Plot plot = generator.generate();

        // Generate the chart
        JFreeChart chart = new JFreeChart(plot);
        chart.setAntiAlias(true);
        chart.setTextAntiAlias(true);
        chart.setBorderVisible(false);
        chart.removeLegend();

        String title = req.getParameter("title");
        if (title != null) {
            chart.setTitle(title);
        }

        // Write the chart to a byte array. It is small enough so it won't load the
        // server's memory too much.
        try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
            ChartUtilities.writeChartAsPNG(baos, chart, IMAGE_WIDTH, IMAGE_HEIGHT);
            byte[] data = baos.toByteArray();

            // Stream the chart
            resp.setContentType("image/png");
            resp.setContentLength(data.length);
            resp.setHeader("Cache-Control", "no-cache, must-revalidate");
            resp.setHeader("Expires", "Sat, 01 Jan 2000 00:00:00 GMT");
            resp.getOutputStream().write(data);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }

}