Java tutorial
/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org. All rights reserved. * This code is licensed under the GPL 2.0 license, availible at the root * application directory. */ package org.vfny.geoserver.config.web; import org.apache.commons.digester.Digester; import org.apache.struts.Globals; import org.apache.struts.action.ActionServlet; import org.apache.struts.config.FormBeanConfig; import org.apache.struts.config.ModuleConfig; import org.apache.struts.config.ModuleConfigFactory; import org.springframework.core.io.Resource; import org.springframework.web.context.support.WebApplicationContextUtils; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import java.io.IOException; import java.io.InputStream; import java.net.MalformedURLException; import java.net.URL; import java.util.Enumeration; import javax.servlet.ServletException; import javax.servlet.UnavailableException; public class MultipleActionServlet extends ActionServlet { /** * */ private static final long serialVersionUID = -5222456011963238678L; /** * <p>Initialize this servlet. Most of the processing has been factored into * support methods so that you can override particular functionality at a * fairly granular level.</p> * * @exception ServletException if we cannot configure ourselves correctly */ public void init() throws ServletException { // Wraps the entire initialization in a try/catch to better handle // unexpected exceptions and errors to provide better feedback // to the developer try { initInternal(); initOther(); initServlet(); getServletContext().setAttribute(Globals.ACTION_SERVLET_KEY, this); initModuleConfigFactory(); // Initialize modules as needed ModuleConfig moduleConfig = initModuleConfig("", config); initModuleMessageResources(moduleConfig); initModuleDataSources(moduleConfig); initModulePlugIns(moduleConfig); moduleConfig.freeze(); Enumeration names = getServletConfig().getInitParameterNames(); while (names.hasMoreElements()) { String name = (String) names.nextElement(); if (!name.startsWith("config/")) { continue; } String prefix = name.substring(6); moduleConfig = initModuleConfig(prefix, getServletConfig().getInitParameter(name)); initModuleMessageResources(moduleConfig); initModuleDataSources(moduleConfig); initModulePlugIns(moduleConfig); moduleConfig.freeze(); } this.initModulePrefixes(this.getServletContext()); this.destroyConfigDigester(); } catch (UnavailableException ex) { throw ex; } catch (Throwable t) { // The follow error message is not retrieved from internal message // resources as they may not have been able to have been // initialized log.error("Unable to initialize Struts ActionServlet due to an " + "unexpected exception or error thrown, so marking the " + "servlet as unavailable. Most likely, this is due to an " + "incorrect or missing library dependency.", t); throw new UnavailableException(t.getMessage()); } } /** * <p>Initialize the module configuration information for the * specified module.</p> * * @param prefix Module prefix for this module * @param paths Comma-separated list of context-relative resource path(s) * for this modules's configuration resource(s) * * @exception ServletException if initialization cannot be performed * @since Struts 1.1 */ protected ModuleConfig initModuleConfig(String prefix, String paths) throws ServletException { // :FIXME: Document UnavailableException? (Doesn't actually throw anything) if (log.isDebugEnabled()) { log.debug("Initializing module path '" + prefix + "' configuration from '" + paths + "'"); } // Parse the configuration for this module ModuleConfigFactory factoryObject = ModuleConfigFactory.createFactory(); ModuleConfig config = factoryObject.createModuleConfig(prefix); // Configure the Digester instance we will use Digester digester = initConfigDigester(); // Process each specified resource path while (paths.length() > 0) { digester.push(config); String path = null; int comma = paths.indexOf(','); if (comma >= 0) { path = paths.substring(0, comma).trim(); paths = paths.substring(comma + 1); } else { path = paths.trim(); paths = ""; } if (path.length() < 1) { break; } this.parseModuleConfigFile(digester, path, config); } getServletContext().setAttribute(Globals.MODULE_KEY + config.getPrefix(), config); // Force creation and registration of DynaActionFormClass instances // for all dynamic form beans we wil be using FormBeanConfig[] fbs = config.findFormBeanConfigs(); for (int i = 0; i < fbs.length; i++) { if (fbs[i].getDynamic()) { fbs[i].getDynaActionFormClass(); } } return config; } /** * <p>Parses one module config file.</p> * * @param digester Digester instance that does the parsing * @param path The path to the config file to parse. * @param config * * @throws UnavailableException if file cannot be read or parsed * @since Struts 1.2 */ protected void parseModuleConfigFile(Digester digester, String path, ModuleConfig config) throws UnavailableException { InputStream input = null; Resource[] resources = null; try { resources = WebApplicationContextUtils.getWebApplicationContext(getServletContext()).getResources(path); } catch (IOException ex) { handleConfigException(path, ex); } final int length = resources.length; for (int i = 0; i < length; i++) { try { URL url = resources[i].getURL(); /*getServletContext().getResource(path)*/ ; // If the config isn't in the servlet context, try the class loader // which allows the config files to be stored in a jar if (url == null) { url = getClass().getResource(path); } if (url == null) { String msg = internal.getMessage("configMissing", path); log.error(msg); throw new UnavailableException(msg); } InputSource is = new InputSource(url.toExternalForm()); input = url.openStream(); is.setByteStream(input); digester.parse(is); } catch (MalformedURLException e) { handleConfigException(path, e); } catch (IOException e) { handleConfigException(path, e); } catch (SAXException e) { handleConfigException(path, e); } finally { if (input != null) { try { input.close(); if ((length > 1) && (i < (length - 1))) { digester.push(config); } } catch (IOException e) { throw new UnavailableException(e.getMessage()); } } } } } /** * <p>Simplifies exception handling in the <code>parseModuleConfigFile</code> method.<p> * @param path * @param e * @throws UnavailableException as a wrapper around Exception */ private void handleConfigException(String path, Exception e) throws UnavailableException { String msg = internal.getMessage("configParse", path); log.error(msg, e); throw new UnavailableException(msg); } }