com.hmsinc.epicenter.webapp.chart.ChartRenderingController.java Source code

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Here is the source code for com.hmsinc.epicenter.webapp.chart.ChartRenderingController.java

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/**
 * Copyright (C) 2008 University of Pittsburgh
 * 
 * 
 * This file is part of Open EpiCenter
 * 
 *     Open EpiCenter 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.
 * 
 *     Open EpiCenter 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 Open EpiCenter.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * 
 *   
 */
package com.hmsinc.epicenter.webapp.chart;

import java.io.IOException;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletResponse;

import net.sf.ehcache.Cache;
import net.sf.ehcache.Element;

import org.apache.commons.lang.Validate;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * Renders cached charts as PNG images.
 * 
 * @author shade
 * @version $Id: ChartRenderingController.java 1059 2008-02-21 19:30:25Z steve.kondik $
 */
@Controller
public class ChartRenderingController {

    @Resource
    private Cache chartCache;

    /**
     * @param id
     * @param width
     * @param height
     * @param response
     * @throws IOException
     */
    @RequestMapping("/chart")
    public void getChart(@RequestParam("id") final String id, @RequestParam("width") final int width,
            @RequestParam("height") final int height, final HttpServletResponse response) throws IOException {

        Validate.notNull(id, "No chart specified.");
        Validate.notNull(width, "No width specified.");
        Validate.notNull(height, "No height specified.");

        final Element e = chartCache.get(id);
        Validate.notNull(e, "Invalid chart id " + id);

        final JFreeChart chart = (JFreeChart) e.getObjectValue();
        Validate.notNull(chart, "Chart was null!");

        response.setContentType("image/png");
        response.addHeader("cache-control", "must-revalidate");

        ChartUtilities.writeChartAsPNG(response.getOutputStream(), chart, width, height);

    }

}