/**
* The contents of this file are subject to the OpenMRS Public License
* Version 1.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://license.openmrs.org
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
* License for the specific language governing rights and limitations
* under the License.
*
* Copyright (C) OpenMRS, LLC. All Rights Reserved.
*/
package org.openmrs.web.servlet;
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.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
public abstract class AbstractGraphServlet extends HttpServlet {
public static final long serialVersionUID = 1231231L;
private Log log = LogFactory.getLog(AbstractGraphServlet.class);
// Supported mime types
public static final String PNG_MIME_TYPE = "image/png";
public static final String JPG_MIME_TYPE = "image/jpeg";
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
// Set default values
Integer width = new Integer(500);
Integer height = new Integer(300);
String mimeType = PNG_MIME_TYPE;
// Retrieve custom values
try {
width = Integer.parseInt(request.getParameter("width"));
}
catch (Exception e) {}
try {
height = Integer.parseInt(request.getParameter("height"));
}
catch (Exception e) {}
if (request.getParameter("mimeType") != null) {
mimeType = request.getParameter("mimeType");
}
JFreeChart chart = createChart(request, response);
// Modify response to disable caching
response.setHeader("Pragma", "No-cache");
response.setDateHeader("Expires", 0);
response.setHeader("Cache-Control", "no-cache");
// Write chart out to response as image
try {
if (JPG_MIME_TYPE.equalsIgnoreCase(mimeType)) {
response.setContentType(JPG_MIME_TYPE);
ChartUtilities.writeChartAsJPEG(response.getOutputStream(), chart, width, height);
} else if (PNG_MIME_TYPE.equalsIgnoreCase(mimeType)) {
response.setContentType(PNG_MIME_TYPE);
ChartUtilities.writeChartAsPNG(response.getOutputStream(), chart, width, height);
} else {
// Throw exception: unsupported mime type
}
}
catch (IOException e) {
log.error(e);
}
}
// Add error handling above and remove this try/catch
catch (Exception e) {
log.error(e);
}
}
/**
* Override this method for each graph
*
* @param request
* @param response
* @return
*/
protected abstract JFreeChart createChart(HttpServletRequest request, HttpServletResponse response);
/**
*
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}