Source code: org/apache/turbine/Turbine.java

   package org.apache.turbine;
   
   /*
    * Copyright 2001-2005 The Apache Software Foundation.
    *
    * Licensed 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.
   */
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  
  import java.util.Properties;
  
  import javax.servlet.ServletConfig;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.commons.configuration.Configuration;
  import org.apache.commons.configuration.ConfigurationFactory;
  import org.apache.commons.configuration.PropertiesConfiguration;
  
  import org.apache.commons.lang.StringUtils;
  
  import org.apache.commons.lang.exception.ExceptionUtils;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.log4j.PropertyConfigurator;
  
  import org.apache.turbine.modules.ActionLoader;
  import org.apache.turbine.modules.PageLoader;
  
  import org.apache.turbine.services.ServiceManager;
  import org.apache.turbine.services.TurbineServices;
  import org.apache.turbine.services.avaloncomponent.AvalonComponentService;
  import org.apache.turbine.services.component.ComponentService;
  import org.apache.turbine.services.template.TemplateService;
  import org.apache.turbine.services.template.TurbineTemplate;
  import org.apache.turbine.services.rundata.RunDataService;
  import org.apache.turbine.services.rundata.TurbineRunDataFacade;
  import org.apache.turbine.services.velocity.VelocityService;
  
  import org.apache.turbine.util.RunData;
  import org.apache.turbine.util.ServerData;
  import org.apache.turbine.util.TurbineConfig;
  import org.apache.turbine.util.TurbineException;
  import org.apache.turbine.util.security.AccessControlList;
  import org.apache.turbine.util.template.TemplateInfo;
  import org.apache.turbine.util.uri.URIConstants;
  
  /**
   * Turbine is the main servlet for the entire system. It is <code>final</code>
   * because you should <i>not</i> ever need to subclass this servlet.  If you
   * need to perform initialization of a service, then you should implement the
   * Services API and let your code be initialized by it.
   * If you need to override something in the <code>doGet()</code> or
   * <code>doPost()</code> methods, edit the TurbineResources.properties file and
   * specify your own classes there.
   * <p>
   * Turbine servlet recognizes the following initialization parameters.
   * <ul>
   * <li><code>properties</code> the path to TurbineResources.properties file
   * used by the default implementation of <code>ResourceService</code>, relative
   * to the application root.</li>
   * <li><code>basedir</code> this parameter is used <strong>only</strong> if your
   * application server does not support web applications, or the or does not
   * support <code>ServletContext.getRealPath(String)</code> method correctly.
   * You can use this parameter to specify the directory within the server's
   * filesystem, that is the base of your web application.</li>
   * </ul>
   *
   * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
   * @author <a href="mailto:bmclaugh@algx.net">Brett McLaughlin</a>
   * @author <a href="mailto:greg@shwoop.com">Greg Ritter</a>
   * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
   * @author <a href="mailto:frank.kim@clearink.com">Frank Y. Kim</a>
   * @author <a href="mailto:krzewski@e-point.pl">Rafal Krzewski</a>
   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
   * @author <a href="mailto:sean@informage.net">Sean Legassick</a>
   * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
   * @author <a href="mailto:quintonm@bellsouth.net">Quinton McCombs</a>
  * @author <a href="mailto:epugh@upstate.com">Eric Pugh</a>
  * @version $Id: Turbine.java 264152 2005-08-29 14:50:22Z henning $
  */
 public class Turbine
         extends HttpServlet
         implements TurbineConstants
 {
     /** SerialVersionUID for serialization */
     private static final long serialVersionUID = -6895381097045304308L;
 
     /**
      * Name of path info parameter used to indicate the redirected stage of
      * a given user's initial Turbine request
      */
     public static final String REDIRECTED_PATHINFO_NAME = "redirected";
 
     /** The base directory key */
     public static final String BASEDIR_KEY = "basedir";
 
     /**
      * In certain situations the init() method is called more than once,
      * somtimes even concurrently. This causes bad things to happen,
      * so we use this flag to prevent it.
      */
     private static boolean firstInit = true;
 
     /** Whether init succeeded or not. */
     private static Throwable initFailure = null;
 
     /**
      * Should initialization activities be performed during doGet() execution?
      */
     private static boolean firstDoGet = true;
 
     /**
      * Keep all the properties of the web server in a convenient data
      * structure
      */
     private static ServerData serverData = null;
 
     /** The base from which the Turbine application will operate. */
     private static String applicationRoot;
 
     /** Servlet config for this Turbine webapp. */
     private static ServletConfig servletConfig;
 
     /** Servlet context for this Turbine webapp. */
     private static ServletContext servletContext;
 
     /**
      * The webapp root where the Turbine application
      * is running in the servlet container.
      * This might differ from the application root.
      */
     private static String webappRoot;
 
     /** Our internal configuration object */
     private static Configuration configuration = null;
 
     /** A reference to the Template Service */
     private TemplateService templateService = null;
 
     /** A reference to the RunData Service */
     private RunDataService rundataService = null;
 
     /** Default Input encoding if the servlet container does not report an encoding */
     private String inputEncoding = null;
 
     /** Logging class from commons.logging */
     private static Log log = LogFactory.getLog(Turbine.class);
 
     /**
      * This init method will load the default resources from a
      * properties file.
      *
      * This method is called by init(ServletConfig config)
      *
      * @exception ServletException a servlet exception.
      */
     public final void init() throws ServletException
     {
         synchronized (this.getClass())
         {
             super.init();
             ServletConfig config = getServletConfig();
 
             if (!firstInit)
             {
                 log.info("Double initialization of Turbine was attempted!");
                 return;
             }
             // executing init will trigger some static initializers, so we have
             // only one chance.
             firstInit = false;
 
             try
             {
                 ServletContext context = config.getServletContext();
 
                 configure(config, context);
 
                 templateService = TurbineTemplate.getService();
                 rundataService = TurbineRunDataFacade.getService();
 
                 if (rundataService == null)
                 {
                     throw new TurbineException(
                             "No RunData Service configured!");
                 }
 
             }
             catch (Exception e)
             {
                 // save the exception to complain loudly later :-)
                 initFailure = e;
                 log.fatal("Turbine: init() failed: ", e);
                 throw new ServletException("Turbine: init() failed", e);
             }
             log.info("Turbine: init() Ready to Rumble!");
         }
     }
 
     /**
      * Read the master configuration file in, configure logging
      * and start up any early services.
      *
      * @param config The Servlet Configuration supplied by the container
      * @param context The Servlet Context supplied by the container
      *
      * @throws Exception A problem occured while reading the configuration or performing early startup
      */
 
     private void configure(ServletConfig config, ServletContext context)
             throws Exception
     {
         // Set the application root. This defaults to the webapp
         // context if not otherwise set. This is to allow 2.1 apps
         // to be developed from CVS. This feature will carry over
         // into 3.0.
         applicationRoot = findInitParameter(context, config,
                 APPLICATION_ROOT_KEY,
                 APPLICATION_ROOT_DEFAULT);
 
         webappRoot = config.getServletContext().getRealPath("/");
         // log.info("Web Application root is " + webappRoot);
         // log.info("Application root is "     + applicationRoot);
 
         if (applicationRoot == null || applicationRoot.equals(WEB_CONTEXT))
         {
             applicationRoot = webappRoot;
             // log.info("got empty or 'webContext' Application root. Application root now: " + applicationRoot);
         }
 
         // Set the applicationRoot for this webapp.
         setApplicationRoot(applicationRoot);
 
         // Create any directories that need to be setup for
         // a running Turbine application.
         createRuntimeDirectories(context, config);
 
         //
         // Now we run the Turbine configuration code. There are two ways
         // to configure Turbine:
         //
         // a) By supplying an web.xml init parameter called "configuration"
         //
         // <init-param>
         //   <param-name>configuration</param-name>
         //   <param-value>/WEB-INF/conf/turbine.xml</param-value>
         // </init-param>
         //
         // This loads an XML based configuration file.
         //
         // b) By supplying an web.xml init parameter called "properties"
         //
         // <init-param>
         //   <param-name>properties</param-name>
         //   <param-value>/WEB-INF/conf/TurbineResources.properties</param-value>
         // </init-param>
         //
         // This loads a Properties based configuration file. Actually, these are
         // extended properties as provided by commons-configuration
         //
         // If neither a) nor b) is supplied, Turbine will fall back to the
         // known behaviour of loading a properties file called
         // /WEB-INF/conf/TurbineResources.properties relative to the
         // web application root.
 
         String confFile= findInitParameter(context, config,
                 TurbineConfig.CONFIGURATION_PATH_KEY,
                 null);
 
         String confPath;
         String confStyle = "unset";
 
         if (StringUtils.isNotEmpty(confFile))
         {
             confPath = getRealPath(confFile);
             ConfigurationFactory configurationFactory = new ConfigurationFactory(confPath);
             configurationFactory.setBasePath(getApplicationRoot());
             configuration = configurationFactory.getConfiguration();
             confStyle = "XML";
         }
         else
         {
             confFile = findInitParameter(context, config,
                     TurbineConfig.PROPERTIES_PATH_KEY,
                     TurbineConfig.PROPERTIES_PATH_DEFAULT);
 
             confPath = getRealPath(confFile);
 
             // This should eventually be a Configuration
             // interface so that service and app configuration
             // can be stored anywhere.
             configuration = (Configuration) new PropertiesConfiguration(confPath);
             confStyle = "Properties";
         }
 
 
         //
         // Set up logging as soon as possible
         //
         String log4jFile = configuration.getString(LOG4J_CONFIG_FILE,
                                                    LOG4J_CONFIG_FILE_DEFAULT);
 
         if (StringUtils.isNotEmpty(log4jFile) &&
                 !log4jFile.equalsIgnoreCase("none"))
         {
             log4jFile = getRealPath(log4jFile);
 
             //
             // Load the config file above into a Properties object and
             // fix up the Application root
             //
             Properties p = new Properties();
             try
             {
                 p.load(new FileInputStream(log4jFile));
                 p.setProperty(APPLICATION_ROOT_KEY, getApplicationRoot());
                 PropertyConfigurator.configure(p);
 
                 log.info("Configured log4j from " + log4jFile);
             }
             catch (FileNotFoundException fnf)
             {
                 System.err.println("Could not open Log4J configuration file "
                         + log4jFile + ": ");
                 fnf.printStackTrace();
             }
         }
 
         // Now report our successful configuration to the world
         log.info("Loaded configuration  (" + confStyle + ") from " + confFile + " (" + confPath + ")");
 
 
         setTurbineServletConfig(config);
         setTurbineServletContext(context);
 
         getServiceManager().setApplicationRoot(applicationRoot);
 
         // We want to set a few values in the configuration so
         // that ${variable} interpolation will work for
         //
         // ${applicationRoot}
         // ${webappRoot}
         configuration.setProperty(APPLICATION_ROOT_KEY, applicationRoot);
         configuration.setProperty(WEBAPP_ROOT_KEY, webappRoot);
 
 
         //
         // Be sure, that our essential services get run early
         //
         configuration.setProperty(TurbineServices.SERVICE_PREFIX +
                                   ComponentService.SERVICE_NAME + ".earlyInit",
                                   Boolean.TRUE);
 
         configuration.setProperty(TurbineServices.SERVICE_PREFIX +
                                   AvalonComponentService.SERVICE_NAME + ".earlyInit",
                                   Boolean.TRUE);
 
         getServiceManager().setConfiguration(configuration);
 
         // Initialize the service manager. Services
         // that have its 'earlyInit' property set to
         // a value of 'true' will be started when
         // the service manager is initialized.
         getServiceManager().init();
 
         // Get the default input encoding
         inputEncoding = configuration.getString(
                 TurbineConstants.PARAMETER_ENCODING_KEY,
                 TurbineConstants.PARAMETER_ENCODING_DEFAULT);
 
         if (log.isDebugEnabled())
         {
             log.debug("Input Encoding has been set to " + inputEncoding);
         }
     }
 
     /**
      * Create any directories that might be needed during
      * runtime. Right now this includes:
      *
      * <ul>
      *
      * <li>The directory to write the log files to (relative to the
      * web application root), or <code>null</code> for the default of
      * <code>/logs</code>.  The directory is specified via the {@link
      * TurbineConstants#LOGGING_ROOT} parameter.</li>
      *
      * </ul>
      *
      * @param context Global initialization parameters.
      * @param config Initialization parameters specific to the Turbine
      * servlet.
      */
     private static void createRuntimeDirectories(ServletContext context,
                                                  ServletConfig config)
     {
         String path = findInitParameter(context, config,
                                         LOGGING_ROOT_KEY,
                                         LOGGING_ROOT_DEFAULT);
 
         File logDir = new File(getRealPath(path));
         if (!logDir.exists())
         {
             // Create the logging directory
             if (!logDir.mkdirs())
             {
                 System.err.println("Cannot create directory for logs!");
             }
         }
     }
 
     /**
      * Finds the specified servlet configuration/initialization
      * parameter, looking first for a servlet-specific parameter, then
      * for a global parameter, and using the provided default if not
      * found.
      */
     protected static final String findInitParameter(ServletContext context,
             ServletConfig config, String name, String defaultValue)
     {
         String path = null;
 
         // Try the name as provided first.
         boolean usingNamespace = name.startsWith(CONFIG_NAMESPACE);
         while (true)
         {
             path = config.getInitParameter(name);
             if (StringUtils.isEmpty(path))
             {
                 path = context.getInitParameter(name);
                 if (StringUtils.isEmpty(path))
                 {
                     // The named parameter didn't yield a value.
                     if (usingNamespace)
                     {
                         path = defaultValue;
                     }
                     else
                     {
                         // Try again using Turbine's namespace.
                         name = CONFIG_NAMESPACE + '.' + name;
                         usingNamespace = true;
                         continue;
                     }
                 }
             }
             break;
         }
 
         return path;
     }
 
     /**
      * Initializes the services which need <code>RunData</code> to
      * initialize themselves (post startup).
      *
      * @param data The first <code>GET</code> request.
      */
     public final void init(RunData data)
     {
         synchronized (Turbine.class)
         {
             if (firstDoGet)
             {
                 // All we want to do here is save some servlet
                 // information so that services and processes
                 // that don't have direct access to a RunData
                 // object can still know something about
                 // the servlet environment.
                 saveServletInfo(data);
 
                 // Mark that we're done.
                 firstDoGet = false;
                 log.info("Turbine: first Request successful");
             }
         }
     }
 
     /**
      * Return the current configuration with all keys included
      *
      * @return a Configuration Object
      */
     public static Configuration getConfiguration()
     {
         return configuration;
     }
 
     /**
      * Return the server name.
      *
      * @return String server name
      */
     public static String getServerName()
     {
         return getDefaultServerData().getServerName();
     }
 
     /**
      * Return the server scheme.
      *
      * @return String server scheme
      */
     public static String getServerScheme()
     {
         return getDefaultServerData().getServerScheme();
     }
 
     /**
      * Return the server port.
      *
      * @return String server port
      */
     public static String getServerPort()
     {
         return Integer.toString(getDefaultServerData().getServerPort());
     }
 
     /**
      * Get the script name. This is the initial script name.
      * Actually this is probably not needed any more. I'll
      * check. jvz.
      *
      * @return String initial script name.
      */
     public static String getScriptName()
     {
         return getDefaultServerData().getScriptName();
     }
 
     /**
      * Return the context path.
      *
      * @return String context path
      */
     public static String getContextPath()
     {
         return getDefaultServerData().getContextPath();
     }
 
     /**
      * Return all the Turbine Servlet information (Server Name, Port,
      * Scheme in a ServerData structure. This is generated from the
      * values set when initializing the Turbine and may not be correct
      * if you're running in a clustered structure. This might be used
      * if you need a DataURI and have no RunData object handy-
      *
      * @return An initialized ServerData object
      */
     public static ServerData getDefaultServerData()
     {
         if(serverData == null)
         {
             log.error("ServerData Information requested from Turbine before first request!");
             // Will be overwritten once the first request is run;
             serverData = new ServerData(null, URIConstants.HTTP_PORT,
                     URIConstants.HTTP, null, null);
         }
         return serverData;
     }
 
     /**
      * Set the servlet config for this turbine webapp.
      *
      * @param config New servlet config
      */
     public static void setTurbineServletConfig(ServletConfig config)
     {
         servletConfig = config;
     }
 
     /**
      * Get the servlet config for this turbine webapp.
      *
      * @return ServletConfig
      */
     public static ServletConfig getTurbineServletConfig()
     {
         return servletConfig;
     }
 
     /**
      * Set the servlet context for this turbine webapp.
      *
      * @param context New servlet context.
      */
     public static void setTurbineServletContext(ServletContext context)
     {
         servletContext = context;
     }
 
     /**
      * Get the servlet context for this turbine webapp.
      *
      * @return ServletContext
      */
     public static ServletContext getTurbineServletContext()
     {
         return servletContext;
     }
 
     /**
      * The <code>Servlet</code> destroy method.  Invokes
      * <code>ServiceBroker</code> tear down method.
      */
     public final void destroy()
     {
         // Shut down all Turbine Services.
         getServiceManager().shutdownServices();
         System.gc();
 
         firstInit = true;
         firstDoGet = true;
         log.info("Turbine: Done shutting down!");
     }
 
     /**
      * The primary method invoked when the Turbine servlet is executed.
      *
      * @param req Servlet request.
      * @param res Servlet response.
      * @exception IOException a servlet exception.
      * @exception ServletException a servlet exception.
      */
     public final void doGet(HttpServletRequest req, HttpServletResponse res)
             throws IOException, ServletException
     {
         // set to true if the request is to be redirected by the page
         boolean requestRedirected = false;
 
         // Placeholder for the RunData object.
         RunData data = null;
         try
         {
             // Check to make sure that we started up properly.
             if (initFailure != null)
             {
                 throw initFailure;
             }
 
             //
             // If the servlet container gives us no clear indication about the
             // Encoding of the contents, set it to our default value.
             if (req.getCharacterEncoding() == null)
             {
                 if (log.isDebugEnabled())
                 {
                     log.debug("Changing Input Encoding to " + inputEncoding);
                 }
 
                 try
                 {
                     req.setCharacterEncoding(inputEncoding);
                 }
                 catch (UnsupportedEncodingException uee)
                 {
                     log.warn("Could not change request encoding to " + inputEncoding, uee);
                 }
             }
 
             // Get general RunData here...
             // Perform turbine specific initialization below.
             data = rundataService.getRunData(req, res, getServletConfig());
 
             // If this is the first invocation, perform some
             // initialization.  Certain services need RunData to initialize
             // themselves.
             if (firstDoGet)
             {
                 init(data);
             }
 
             // set the session timeout if specified in turbine's properties
             // file if this is a new session
             if (data.getSession().isNew())
             {
                 int timeout = configuration.getInt(SESSION_TIMEOUT_KEY,
                                                    SESSION_TIMEOUT_DEFAULT);
 
                 if (timeout != SESSION_TIMEOUT_DEFAULT)
                 {
                     data.getSession().setMaxInactiveInterval(timeout);
                 }
             }
 
             // Fill in the screen and action variables.
             data.setScreen(data.getParameters().getString(URIConstants.CGI_SCREEN_PARAM));
             data.setAction(data.getParameters().getString(URIConstants.CGI_ACTION_PARAM));
 
             // Special case for login and logout, this must happen before the
             // session validator is executed in order either to allow a user to
             // even login, or to ensure that the session validator gets to
             // mandate its page selection policy for non-logged in users
             // after the logout has taken place.
             if (data.hasAction())
             {
                 String action = data.getAction();
                 log.debug("action = " + action);
 
                 if (action.equalsIgnoreCase(
                         configuration.getString(ACTION_LOGIN_KEY,
                                                 ACTION_LOGIN_DEFAULT)))
                 {
                     loginAction(data);
                 }
                 else if (action.equalsIgnoreCase(
                         configuration.getString(ACTION_LOGOUT_KEY,
                                                 ACTION_LOGOUT_DEFAULT)))
                 {
                    logoutAction(data);
                 }
             }
 
             // This is where the validation of the Session information
             // is performed if the user has not logged in yet, then
             // the screen is set to be Login. This also handles the
             // case of not having a screen defined by also setting the
             // screen to Login. If you want people to go to another
             // screen other than Login, you need to change that within
             // TurbineResources.properties...screen.homepage; or, you
             // can specify your own SessionValidator action.
             ActionLoader.getInstance().exec(
                     data, configuration.getString(ACTION_SESSION_VALIDATOR_KEY,
                         ACTION_SESSION_VALIDATOR_DEFAULT));
 
             // Put the Access Control List into the RunData object, so
             // it is easily available to modules.  It is also placed
             // into the session for serialization.  Modules can null
             // out the ACL to force it to be rebuilt based on more
             // information.
             ActionLoader.getInstance().exec(
                     data, configuration.getString(ACTION_ACCESS_CONTROLLER_KEY,
                         ACTION_ACCESS_CONTROLLER_DEFAULT));
 
             // Start the execution phase. DefaultPage will execute the
             // appropriate action as well as get the Layout from the
             // Screen and then execute that. The Layout is then
             // responsible for executing the Navigation and Screen
             // modules.
             //
             // Note that by default, this cannot be overridden from
             // parameters passed in via post/query data. This is for
             // security purposes.  You should really never need more
             // than just the default page.  If you do, add logic to
             // DefaultPage to do what you want.
 
             String defaultPage = (templateService == null)
                     ? null :templateService.getDefaultPageName(data);
 
             if (defaultPage == null)
             {
                 /*
                  * In this case none of the template services are running.
                  * The application may be using ECS for views, or a
                  * decendent of RawScreen is trying to produce output.
                  * If there is a 'page.default' property in the TR.props
                  * then use that, otherwise return DefaultPage which will
                  * handle ECS view scenerios and RawScreen scenerios. The
                  * app developer can still specify the 'page.default'
                  * if they wish but the DefaultPage should work in
                  * most cases.
                  */
                 defaultPage = configuration.getString(PAGE_DEFAULT_KEY,
                         PAGE_DEFAULT_DEFAULT);
             }
 
             PageLoader.getInstance().exec(data, defaultPage);
 
             // If a module has set data.acl = null, remove acl from
             // the session.
             if (data.getACL() == null)
             {
                 try
                 {
                     data.getSession().removeAttribute(
                             AccessControlList.SESSION_KEY);
                 }
                 catch (IllegalStateException ignored)
                 {
                 }
             }
 
             // handle a redirect request
             requestRedirected = ((data.getRedirectURI() != null)
                                  && (data.getRedirectURI().length() > 0));
             if (requestRedirected)
             {
                 if (data.getResponse().isCommitted())
                 {
                     requestRedirected = false;
                     log.warn("redirect requested, response already committed: " +
                              data.getRedirectURI());
                 }
                 else
                 {
                     data.getResponse().sendRedirect(data.getRedirectURI());
                 }
             }
 
             if (!requestRedirected)
             {
                 try
                 {
                     if (data.isPageSet() == false && data.isOutSet() == false)
                     {
                         throw new Exception("Nothing to output");
                     }
 
                     // We are all done! if isPageSet() output that way
                     // otherwise, data.getOut() has already been written
                     // to the data.getOut().close() happens below in the
                     // finally.
                     if (data.isPageSet() && data.isOutSet() == false)
                     {
                         // Modules can override these.
                         data.getResponse().setLocale(data.getLocale());
                         data.getResponse().setContentType(
                                 data.getContentType());
 
                         // Set the status code.
                         data.getResponse().setStatus(data.getStatusCode());
                         // Output the Page.
                         data.getPage().output(data.getOut());
                     }
                 }
                 catch (Exception e)
                 {
                     // The output stream was probably closed by the client
                     // end of things ie: the client clicked the Stop
                     // button on the browser, so ignore any errors that
                     // result.
                     log.debug("Output stream closed? ", e);
                 }
             }
         }
         catch (Exception e)
         {
             handleException(data, res, e);
         }
         catch (Throwable t)
         {
             handleException(data, res, t);
         }
         finally
         {
             // Return the used RunData to the factory for recycling.
             rundataService.putRunData(data);
         }
     }
 
     /**
      * In this application doGet and doPost are the same thing.
      *
      * @param req Servlet request.
      * @param res Servlet response.
      * @exception IOException a servlet exception.
      * @exception ServletException a servlet exception.
      */
     public final void doPost(HttpServletRequest req, HttpServletResponse res)
             throws IOException, ServletException
     {
         doGet(req, res);
     }
 
     /**
      * This method is executed if the configured Login action should be
      * executed by Turbine.
      * <p>
      * This Action must be performed before the Session validation or we
      * get sent in an endless loop back to the Login screen before
      * the action can be performed
      *
      * @param data a RunData object
      *
      * @throws Exception A problem while logging in occured.
      */
     private void loginAction(RunData data)
             throws Exception
     {
         ActionLoader.getInstance().exec(data, data.getAction());
         cleanupTemplateContext(data);
         data.setAction(null);
     }
 
     /**
      * This method is executed if the configured Logout action should be
      * executed by Turbine.
      * <p>
      * This Action must be performed before the Session validation for the
      * session validator to send us back to the Login screen.
      * <p>
      * The existing session is invalidated before the logout action is
      * executed.
      *
      * @param data a RunData object
      *
      * @throws Exception A problem while logging out occured.
      */
     private void logoutAction(RunData data)
             throws Exception
     {
         ActionLoader.getInstance().exec(data, data.getAction());
         cleanupTemplateContext(data);
         data.setAction(null);
         data.getSession().invalidate();
     }
 
     /**
      * cleans the Velocity Context if available.
      *
      * @param data A RunData Object
      *
      * @throws Exception A problem while cleaning out the Template Context occured.
      */
     private void cleanupTemplateContext(RunData data)
             throws Exception
     {
         // This is Velocity specific and shouldn't be done here.
         // But this is a band aid until we get real listeners
         // here.
         TemplateInfo ti = data.getTemplateInfo();
         if (ti != null)
         {
             ti.removeTemp(VelocityService.CONTEXT);
         }
     }
 
     /**
      * Return the servlet info.
      *
      * @return a string with the servlet information.
      */
     public final String getServletInfo()
     {
         return "Turbine Servlet";
     }
 
     /**
      * This method is about making sure that we catch and display
      * errors to the screen in one fashion or another. What happens is
      * that it will attempt to show the error using your user defined
      * Error Screen. If that fails, then it will resort to just
      * displaying the error and logging it all over the place
      * including the servlet engine log file, the Turbine log file and
      * on the screen.
      *
      * @param data A Turbine RunData object.
      * @param res Servlet response.
      * @param t The exception to report.
      */
     private void handleException(RunData data, HttpServletResponse res,
                                        Throwable t)
     {
         // make sure that the stack trace makes it the log
         log.error("Turbine.handleException: ", t);
 
         String mimeType = "text/plain";
         try
         {
             // This is where we capture all exceptions and show the
             // Error Screen.
             data.setStackTrace(ExceptionUtils.getStackTrace(t), t);
 
             // setup the screen
             data.setScreen(configuration.getString(SCREEN_ERROR_KEY,
                     SCREEN_ERROR_DEFAULT));
 
             // do more screen setup for template execution if needed
             if (data.getTemplateInfo() != null)
             {
                 data.getTemplateInfo()
                     .setScreenTemplate(configuration.getString(
                             TEMPLATE_ERROR_KEY, TEMPLATE_ERROR_VM));
             }
 
             // Make sure to not execute an action.
             data.setAction("");

            PageLoader.getInstance().exec(data,
                    configuration.getString(PAGE_DEFAULT_KEY,
                            PAGE_DEFAULT_DEFAULT));

            data.getResponse().setContentType(data.getContentType());
            data.getResponse().setStatus(data.getStatusCode());
            if (data.isPageSet())
            {
                data.getOut().print(data.getPage().toString());
            }
        }
        // Catch this one because it occurs if some code hasn't been
        // completely re-compiled after a change..
        catch (java.lang.NoSuchFieldError e)
        {
            try
            {
                data.getResponse().setContentType(mimeType);
                data.getResponse().setStatus(200);
            }
            catch (Exception ignored)
            {
                // Ignored
            }

            try
            {
                data.getOut().print("java.lang.NoSuchFieldError: "
                        + "Please recompile all of your source code.");
            }
            catch (IOException ignored)
            {
            }

            log.error(data.getStackTrace(), e);
        }
        // Attempt to do *something* at this point...
        catch (Throwable reallyScrewedNow)
        {
            StringBuffer msg = new StringBuffer();
            msg.append("Horrible Exception: ");
            if (data != null)
            {
                msg.append(data.getStackTrace());
            }
            else
            {
                msg.append(t);
            }
            try
            {
                res.setContentType(mimeType);
                res.setStatus(200);
                res.getWriter().print(msg.toString());
            }
            catch (Exception ignored)
            {
            }

            log.error(reallyScrewedNow.getMessage(), reallyScrewedNow);
        }
    }

    /**
     * Save some information about this servlet so that
     * it can be utilized by object instances that do not
     * have direct access to RunData.
     *
     * @param data
     */
    public static synchronized void saveServletInfo(RunData data)
    {
        // Store the context path for tools like ContentURI and
        // the UIManager that use webapp context path information
        // for constructing URLs.

        //
        // Bundle all the information above up into a convenient structure
        //
        serverData = (ServerData) data.getServerData().clone();
    }

    /**
     * Set the application root for the webapp.
     *
     * @param val New app root.
     */
    public static void setApplicationRoot(String val)
    {
        applicationRoot = val;
    }

    /**
     * Get the application root for this Turbine webapp. This
     * concept was started in 3.0 and will allow an app to be
     * developed from a standard CVS layout. With a simple
     * switch the app will work fully within the servlet
     * container for deployment.
     *
     * @return String applicationRoot
     */
    public static String getApplicationRoot()
    {
        return applicationRoot;
    }

    /**
     * Used to get the real path of configuration and resource
     * information. This can be used by an app being
     * developed in a standard CVS layout.
     *
     * @param path path translated to the application root
     * @return the real path
     */
    public static String getRealPath(String path)
    {
        if (path.startsWith("/"))
        {
            path = path.substring(1);
        }

        return new File(getApplicationRoot(), path).getAbsolutePath();
    }

    /**
     * Return an instance of the currently configured Service Manager
     *
     * @return A service Manager instance
     */
    private ServiceManager getServiceManager()
    {
        return TurbineServices.getInstance();
    }
}