/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF 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.apache.myfaces.webapp;

 import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam;

 import org.apache.myfaces.config.annotation.LifecycleProviderFactory;

 import org.apache.myfaces.shared.util.ClassUtils;

 import javax.faces.FactoryFinder;

 import javax.faces.context.ExternalContext;

 import javax.faces.context.FacesContext;

 import javax.servlet.ServletContext;

 import javax.servlet.ServletContextAttributeEvent;

 import javax.servlet.ServletContextAttributeListener;

 import javax.servlet.ServletContextEvent;

 import javax.servlet.ServletContextListener;

 import javax.servlet.ServletRequestAttributeEvent;

 import javax.servlet.ServletRequestAttributeListener;

 import javax.servlet.ServletRequestEvent;

 import javax.servlet.ServletRequestListener;

 import javax.servlet.http.HttpSessionAttributeListener;

 import javax.servlet.http.HttpSessionBindingEvent;

 import javax.servlet.http.HttpSessionEvent;

 import javax.servlet.http.HttpSessionListener;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.LinkedList;

 import java.util.List;

 import java.util.Map;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 /**

  * Initialise the MyFaces system.

  * <p/>

  * This context listener is registered by the JSP TLD file for the standard JSF "f" components. Normally, servlet

  * containers will automatically load and process .tld files at startup time, and therefore register and run this class

  * automatically.

  * <p/>

  * Some very old servlet containers do not do this correctly, so in those cases this listener may be registered manually

  * in web.xml. Registering it twice (ie in both .tld and web.xml) will result in a harmless warning message being

  * generated. Very old versions of MyFaces Core do not register the listener in the .tld file, so those also need a

  * manual entry in web.xml. However all versions since at least 1.1.2 have this entry in the tld.

  * <p/>

  * This listener also delegates all session, request and context events to ManagedBeanDestroyer.

  * Because of that we only need to register one listener in the tld.

  *

  * @author Manfred Geiler (latest modification by $Author$)

  * @version $Revision$ $Date$

  */

 public class StartupServletContextListener implements ServletContextListener,

         HttpSessionAttributeListener, HttpSessionListener,

         ServletRequestListener, ServletRequestAttributeListener,

         ServletContextAttributeListener

 {

     static final String FACES_INIT_DONE = "org.apache.myfaces.webapp.StartupServletContextListener.FACES_INIT_DONE";

     /**

      * comma delimited list of plugin classes which can be hooked into myfaces

      */

     @JSFWebConfigParam(since = "2.0")

     static final String FACES_INIT_PLUGINS = "org.apache.myfaces.FACES_INIT_PLUGINS";

     private static final byte FACES_INIT_PHASE_PREINIT = 0;

     private static final byte FACES_INIT_PHASE_POSTINIT = 1;

     private static final byte FACES_INIT_PHASE_PREDESTROY = 2;

     private static final byte FACES_INIT_PHASE_POSTDESTROY = 3;

     //private static final Log log = LogFactory.getLog(StartupServletContextListener.class);

     private static final Logger log = Logger.getLogger(StartupServletContextListener.class.getName());

     private FacesInitializer _facesInitializer;

     private ServletContext _servletContext;

     private ManagedBeanDestroyerListener _detroyerListener = new ManagedBeanDestroyerListener();

     public void contextInitialized(ServletContextEvent event)

     {

         if (_servletContext != null)

         {

             throw new IllegalStateException("context is already initialized");

         }

         _servletContext = event.getServletContext();

         Boolean b = (Boolean) _servletContext.getAttribute(FACES_INIT_DONE);

         if (b == null || b.booleanValue() == false)

         {

             long start = System.currentTimeMillis();

             if (_facesInitializer == null)

             {

                 _facesInitializer = FacesInitializerFactory.getFacesInitializer(_servletContext);

             }

             // Create startup FacesContext before initializing

             FacesContext facesContext = _facesInitializer.initStartupFacesContext(_servletContext);

             // publish the ManagedBeanDestroyerListener instance in the application map

             _publishManagedBeanDestroyerListener(facesContext);

             dispatchInitializationEvent(event, FACES_INIT_PHASE_PREINIT);

             _facesInitializer.initFaces(_servletContext);

             dispatchInitializationEvent(event, FACES_INIT_PHASE_POSTINIT);

             _servletContext.setAttribute(FACES_INIT_DONE, Boolean.TRUE);

             // call contextInitialized on ManagedBeanDestroyerListener

             _detroyerListener.contextInitialized(event);

             //Destroy startup FacesContext

             _facesInitializer.destroyStartupFacesContext(facesContext);

             log.log(Level.INFO, "MyFaces Core has started, it took ["

                     + (System.currentTimeMillis() - start)

                     + "] ms.");

         }

         else

         {

             log.info("MyFaces already initialized");

         }

     }

     /**

      * Publishes the ManagedBeanDestroyerListener instance in the application map.

      * This allows the FacesConfigurator to access the instance and to set the

      * correct ManagedBeanDestroyer instance on it.

      *

      * @param facesContext

      */

     private void _publishManagedBeanDestroyerListener(FacesContext facesContext)

     {

         ExternalContext externalContext = facesContext.getExternalContext();

         Map<String, Object> applicationMap = externalContext.getApplicationMap();

         applicationMap.put(ManagedBeanDestroyerListener.APPLICATION_MAP_KEY, _detroyerListener);

     }

     public void contextDestroyed(ServletContextEvent event)

     {

         if (_facesInitializer != null && _servletContext != null)

         {

             // Create startup FacesContext before start undeploy

             FacesContext facesContext = _facesInitializer.initShutdownFacesContext(_servletContext);

             dispatchInitializationEvent(event, FACES_INIT_PHASE_PREDESTROY);

             // call contextDestroyed on ManagedBeanDestroyerListener to destroy the attributes

             _detroyerListener.contextDestroyed(event);

             _facesInitializer.destroyFaces(_servletContext);

             LifecycleProviderFactory.getLifecycleProviderFactory().release();

             // Destroy startup FacesContext, but note we do before publish postdestroy event on

             // plugins and before release factories.

             if (facesContext != null)

             {

                 _facesInitializer.destroyShutdownFacesContext(facesContext);

             }

             FactoryFinder.releaseFactories();

             //DiscoverSingleton.release(); //clears EnvironmentCache and prevents leaking classloader references

             dispatchInitializationEvent(event, FACES_INIT_PHASE_POSTDESTROY);

         }

         _servletContext = null;

     }

     /**

      * configure the faces initializer

      *

      * @param facesInitializer

      */

     public void setFacesInitializer(FacesInitializer facesInitializer) // TODO who uses this method?

     {

         if (_facesInitializer != null && _facesInitializer != facesInitializer && _servletContext != null)

         {

             _facesInitializer.destroyFaces(_servletContext);

         }

         _facesInitializer = facesInitializer;

         if (_servletContext != null)

         {

             facesInitializer.initFaces(_servletContext);

         }

     }

     /**

      * loads the faces init plugins per reflection and Service loader

      * in a jdk6 environment

      *

      * @return false in case of a failed attempt or no listeners found

      *         which then will cause the jdk5 context.xml code to trigger

      */

     private boolean loadFacesInitPluginsJDK6()

     {

         String[] pluginEntries = null;

         try

         {

             Class serviceLoader = ClassUtils.getContextClassLoader().loadClass("java.util.ServiceLoader");

             Method m = serviceLoader.getDeclaredMethod("load", Class.class, ClassLoader.class);

             Object loader = m.invoke(serviceLoader, StartupListener.class, ClassUtils.getContextClassLoader());

             m = loader.getClass().getDeclaredMethod("iterator");

             Iterator<StartupListener> it = (Iterator<StartupListener>) m.invoke(loader);

             List<StartupListener> listeners = new LinkedList<StartupListener>();

             if (!it.hasNext())

             {

                 return false;

             }

             while (it.hasNext())

             {

                 listeners.add(it.next());

             }

             //StartupListener[] listeners1 = listeners.toArray(new StartupListener[listeners.size()]);

             _servletContext.setAttribute(FACES_INIT_PLUGINS, listeners);

             return true;

         }

         catch (ClassNotFoundException e)

         {

         }

         catch (NoSuchMethodException e)

         {

             log.log(Level.SEVERE, e.getMessage(), e);

         }

         catch (InvocationTargetException e)

         {

             log.log(Level.SEVERE, e.getMessage(), e);

         }

         catch (IllegalAccessException e)

         {

             log.log(Level.SEVERE, e.getMessage(), e);

         }

         return false;

     }

     /**

      * loads the faces init plugins per reflection and Service loader

      * in a jdk6 environment

      */

     private void loadFacesInitPluginsJDK5()

     {

         String plugins = (String) _servletContext.getInitParameter(FACES_INIT_PLUGINS);

         if (plugins == null)

         {

             return;

         }

         log.info("MyFaces Plugins found");

         String[] pluginEntries = plugins.split(",");

         List<StartupListener> listeners = new ArrayList<StartupListener>(pluginEntries.length);

         for (String pluginEntry : pluginEntries)

         {

             try

             {

                 Class pluginClass = null;

                 pluginClass = ClassUtils.getContextClassLoader().loadClass(pluginEntry);

                 if (pluginClass == null)

                 {

                     pluginClass = this.getClass().getClassLoader().loadClass(pluginEntry);

                 }

                 listeners.add((StartupListener) pluginClass.newInstance());

             }

             catch (ClassNotFoundException e)

             {

                 log.log(Level.SEVERE, e.getMessage(), e);

             }

             catch (InstantiationException e)

             {

                 log.log(Level.SEVERE, e.getMessage(), e);

             }

             catch (IllegalAccessException e)

             {

                 log.log(Level.SEVERE, e.getMessage(), e);

             }

         }

         // StartupListener[] listeners1 = listeners.toArray(new StartupListener[listeners.size()]);

         _servletContext.setAttribute(FACES_INIT_PLUGINS, listeners);

     }

     /**

      * the central initialisation event dispatcher which calls

      * our listeners

      *

      * @param event

      * @param operation

      */

     private void dispatchInitializationEvent(ServletContextEvent event, int operation)

     {

         if (operation == FACES_INIT_PHASE_PREINIT)

         {

             if (!loadFacesInitPluginsJDK6())

             {

                 loadFacesInitPluginsJDK5();

             }

         }

         List<StartupListener> pluginEntries = (List<StartupListener>) _servletContext.getAttribute(FACES_INIT_PLUGINS);

         if (pluginEntries == null)

         {

             return;

         }

         //now we process the plugins

         for (StartupListener initializer : pluginEntries)

         {

             log.info("Processing plugin");

             //for now the initializers have to be stateless to

             //so that we do not have to enforce that the initializer

             //must be serializable

             switch (operation)

             {

                 case FACES_INIT_PHASE_PREINIT:

                     initializer.preInit(event);

                     break;

                 case FACES_INIT_PHASE_POSTINIT:

                     initializer.postInit(event);

                     break;

                 case FACES_INIT_PHASE_PREDESTROY:

                     initializer.preDestroy(event);

                     break;

                 default:

                     initializer.postDestroy(event);

                     break;

             }

         }

         log.info("Processing MyFaces plugins done");

     }

     /* the following methods are needed to serve ManagedBeanDestroyerListener */

     /* Session related methods ***********************************************/

     public void attributeAdded(HttpSessionBindingEvent event)

     {

         _detroyerListener.attributeAdded(event);

     }

     public void attributeRemoved(HttpSessionBindingEvent event)

     {

         _detroyerListener.attributeRemoved(event);

     }

     public void attributeReplaced(HttpSessionBindingEvent event)

     {

         _detroyerListener.attributeReplaced(event);

     }

     public void sessionCreated(HttpSessionEvent event)

     {

         _detroyerListener.sessionCreated(event);

     }

     public void sessionDestroyed(HttpSessionEvent event)

     {

         _detroyerListener.sessionDestroyed(event);

     }

     /* Context related methods ***********************************************/

     public void attributeAdded(ServletContextAttributeEvent event)

     {

         _detroyerListener.attributeAdded(event);

     }

     public void attributeRemoved(ServletContextAttributeEvent event)

     {

         _detroyerListener.attributeRemoved(event);

     }

     public void attributeReplaced(ServletContextAttributeEvent event)

     {

         _detroyerListener.attributeReplaced(event);

     }

     /* Request related methods ***********************************************/

     public void attributeAdded(ServletRequestAttributeEvent event)

     {

         _detroyerListener.attributeAdded(event);

     }

     public void attributeRemoved(ServletRequestAttributeEvent event)

     {

         _detroyerListener.attributeRemoved(event);

     }

     public void attributeReplaced(ServletRequestAttributeEvent event)

     {

         _detroyerListener.attributeReplaced(event);

     }

     public void requestInitialized(ServletRequestEvent event)

     {

         _detroyerListener.requestInitialized(event);

     }

     public void requestDestroyed(ServletRequestEvent event)

     {

         _detroyerListener.requestDestroyed(event);

     }

 }