Java tutorial
/** * Copyright (c) 2010, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * WSO2 Inc. licenses this file to you under the Apache License, * Version 2.0 (the "License"); you may not use this file except * in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.wso2.carbon.bpel.ui.bpel2svg; import org.apache.axiom.om.OMElement; import org.apache.axis2.context.ConfigurationContext; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.wso2.carbon.CarbonConstants; import org.wso2.carbon.bpel.stub.mgt.ProcessManagementException; import org.wso2.carbon.bpel.ui.bpel2svg.impl.BPELImpl; import org.wso2.carbon.bpel.ui.bpel2svg.impl.SVGImpl; import org.wso2.carbon.bpel.ui.clients.ProcessManagementServiceClient; import org.wso2.carbon.businessprocesses.common.utils.CharacterEncoder; import org.wso2.carbon.ui.CarbonUIUtil; import org.wso2.carbon.utils.ServerConstants; import java.io.IOException; import java.util.logging.Level; import java.util.logging.Logger; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import javax.xml.namespace.QName; /** * Generate the PNG out of the SVG. May be useful in browsers which doesn't support SVG */ public class PNGGenarateServlet extends HttpServlet { static final long serialVersionUID = 42L; /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { Log log = LogFactory.getLog(PNGGenarateServlet.class); HttpSession session = request.getSession(true); String pid = CharacterEncoder.getSafeText(request.getParameter("pid")); ServletConfig config = getServletConfig(); String backendServerURL = CarbonUIUtil.getServerURL(config.getServletContext(), session); ConfigurationContext configContext = (ConfigurationContext) config.getServletContext() .getAttribute(CarbonConstants.CONFIGURATION_CONTEXT); String cookie = (String) session.getAttribute(ServerConstants.ADMIN_SERVICE_COOKIE); String processDef; ProcessManagementServiceClient client; SVGInterface svg; String svgStr; try { client = new ProcessManagementServiceClient(cookie, backendServerURL, configContext, request.getLocale()); //Gets the bpel process definition needed to create the SVG from the processId processDef = client.getProcessInfo(QName.valueOf(pid)).getDefinitionInfo().getDefinition() .getExtraElement().toString(); BPELInterface bpel = new BPELImpl(); //Converts the bpel process definition to an omElement which is how the AXIS2 Object Model (AXIOM) // represents an XML document OMElement bpelStr = bpel.load(processDef); /** * Process the OmElement containing the bpel process definition * Process the subactivites of the bpel process by iterating through the omElement * */ bpel.processBpelString(bpelStr); //Create a new instance of the LayoutManager for the bpel process LayoutManager layoutManager = BPEL2SVGFactory.getInstance().getLayoutManager(); //Set the layout of the SVG to vertical layoutManager.setVerticalLayout(true); //Get the root activity i.e. the Process Activity layoutManager.layoutSVG(bpel.getRootActivity()); svg = new SVGImpl(); //Set the root activity of the SVG i.e. the Process Activity svg.setRootActivity(bpel.getRootActivity()); //Set the content type of the HTTP response as "image/png" response.setContentType("image/png"); //Create an instance of ServletOutputStream to write the output ServletOutputStream sos = response.getOutputStream(); //Convert the image as a byte array of a PNG byte[] pngBytes = svg.toPNGBytes(); // stream to write binary data into the response sos.write(pngBytes); sos.flush(); sos.close(); } catch (ProcessManagementException e) { log.error("PNG Generation Error", e); } } /** * Handles the HTTP <code>GET</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { processRequest(request, response); } catch (ServletException ex) { Logger.getLogger(PNGGenarateServlet.class.getName()).log(Level.SEVERE, null, ex); } } /** * Handles the HTTP <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { processRequest(request, response); } catch (ServletException ex) { Logger.getLogger(PNGGenarateServlet.class.getName()).log(Level.SEVERE, null, ex); } } }