LightPIT: src/main/java/de/uapcore/lightpit/ModuleManager.java@824d4042c857 (annotated)

src/main/java/de/uapcore/lightpit/ModuleManager.java@824d4042c857 (annotated)

src/main/java/de/uapcore/lightpit/ModuleManager.java

Sat, 09 May 2020 17:01:29 +0200

author: Mike Becker <universe@uap-core.de>
date: Sat, 09 May 2020 17:01:29 +0200
changeset 34: 824d4042c857
parent 33: fd8c40ff78c3
child 36: 0f4f8f255c32
permissions: -rw-r--r--

cleanup and simplification of database access layer

 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
  * Copyright 2018 Mike Becker. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *   1. Redistributions of source code must retain the above copyright
  *      notice, this list of conditions and the following disclaimer.
  *
  *   2. Redistributions in binary form must reproduce the above copyright
  *      notice, this list of conditions and the following disclaimer in the
  *      documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
  */
 package de.uapcore.lightpit;
 import de.uapcore.lightpit.entities.Module;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import javax.servlet.Registration;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletContextEvent;
 import javax.servlet.ServletContextListener;
 import javax.servlet.annotation.WebListener;
 import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 /**
  * Scans registered servlets for LightPIT modules.
  */
 @WebListener
 public final class ModuleManager implements ServletContextListener {
     private static final Logger LOG = LoggerFactory.getLogger(ModuleManager.class);
     /**
      * The attribute name in the servlet context under which an instance of this class can be found.
      */
     public static final String SC_ATTR_NAME = ModuleManager.class.getName();
     private ServletContext sc;
     /**
      * Maps class names to module information.
      */
     private final Map<String, LightPITModule> registeredModules = new HashMap<>();
     /**
      * This flag is true, when synchronization is needed.
      */
     private final AtomicBoolean dirty = new AtomicBoolean(true);
     @Override
     public void contextInitialized(ServletContextEvent sce) {
         sc = sce.getServletContext();
         reloadAll();
         sc.setAttribute(SC_ATTR_NAME, this);
         LOG.info("Module manager injected into ServletContext.");
     }
     @Override
     public void contextDestroyed(ServletContextEvent sce) {
         unloadAll();
     }
     private Optional<LightPITModule> getModuleInfo(Registration reg) {
         try {
             final Class<?> scclass = Class.forName(reg.getClassName());
             final boolean lpservlet = AbstractLightPITServlet.class.isAssignableFrom(scclass);
             final boolean lpmodule = scclass.isAnnotationPresent(LightPITModule.class);
             if (lpservlet && !lpmodule) {
                 LOG.warn(
                         "{} is a LightPIT Servlet but is missing the module annotation.",
                         reg.getClassName()
                 );
             } else if (!lpservlet && lpmodule) {
                 LOG.warn(
                         "{} is annotated as a LightPIT Module but does not extend {}.",
                         reg.getClassName(),
                         AbstractLightPITServlet.class.getSimpleName()
                 );
             }
             if (lpservlet && lpmodule) {
                 final LightPITModule moduleInfo = scclass.getAnnotation(LightPITModule.class);
                 return Optional.of(moduleInfo);
             } else {
                 return Optional.empty();
             }
         } catch (ClassNotFoundException ex) {
             LOG.error(
                     "Servlet registration refers to class {} which cannot be found by the class loader (Reason: {})",
                     reg.getClassName(),
                     ex.getMessage()
             );
             return Optional.empty();
         }
     }
     private void handleServletRegistration(String name, Registration reg) {
         final Optional<LightPITModule> moduleInfo = getModuleInfo(reg);
         if (moduleInfo.isPresent()) {
             registeredModules.put(reg.getClassName(), moduleInfo.get());
             LOG.info("Module detected: {}", name);
         } else {
             LOG.debug("Servlet {} is no module, skipping.", name);
         }
     }
     /**
      * Scans for modules and reloads them all.
      */
     public void reloadAll() {
         registeredModules.clear();
         sc.getServletRegistrations().forEach(this::handleServletRegistration);
         // TODO: implement dependency resolver
         dirty.set(true);
         LOG.info("Modules loaded.");
     }
     /**
      * Synchronizes module information with the database.
      * <p>
      * This must be called from the {@link AbstractLightPITServlet}.
      * Admittedly the call will perform the synchronization once after reload
      * and be a no-op, afterwards.
      * However, since the DatabaseFacade might be loaded after the module
      * manager, we must defer the synchronization to the first request
      * handled by the Servlet.
      *
      * @param db interface to the database
      */
     public void syncWithDatabase(DatabaseFacade db) {
         if (dirty.compareAndSet(true, false)) {
             if (db.getDataSource().isPresent()) {
                 try (Connection conn = db.getDataSource().get().getConnection()) {
                     db.getDataAccessObjects()
                             .getModuleDao()
                             .syncRegisteredModuleClasses(conn, registeredModules.entrySet());
                 } catch (SQLException ex) {
                     LOG.error("Unexpected SQL Exception", ex);
                 }
             } else {
                 LOG.error("No datasource present. Cannot sync module information with database.");
             }
         } else {
             LOG.trace("Module information clean - no synchronization required.");
         }
     }
     /**
      * Unloads all found modules.
      */
     public void unloadAll() {
         registeredModules.clear();
         LOG.info("All modules unloaded.");
     }
     /**
      * Returns the main menu.
      *
      * @param db the interface to the database
      * @return a list of menus belonging to the main menu
      */
     public List<Menu> getMainMenu(DatabaseFacade db) {
         // TODO: user specific menu
         if (db.getDataSource().isPresent()) {
             try (Connection conn = db.getDataSource().get().getConnection()) {
                 final List<Module> modules = db.getDataAccessObjects().getModuleDao().list(conn);
                 return modules
                         .stream()
                         .filter(Module::isVisible)
                         .sorted(new Module.PriorityComparator())
                         .map(mod -> new Menu(
                                 mod.getClassname(),
                                 new ResourceKey(
                                         registeredModules.get(mod.getClassname()).bundleBaseName(),
                                         registeredModules.get(mod.getClassname()).menuKey()),
                                 registeredModules.get(mod.getClassname()).modulePath()))
                         .collect(Collectors.toList());
             } catch (SQLException ex) {
                 LOG.error("Unexpected SQLException when loading the main menu", ex);
                 return Collections.emptyList();
             }
         } else {
             return Collections.emptyList();
         }
     }
     /**
      * Returns an unmodifiable map of all registered modules.
      * <p>
      * The key is the classname of the module.
      *
      * @return the map of registered modules
      */
     public Map<String, LightPITModule> getRegisteredModules() {
         return Collections.unmodifiableMap(registeredModules);
     }
 }

Mercurial > hg > LightPIT / annotate

src/main/java/de/uapcore/lightpit/ModuleManager.java@824d4042c857 (annotated)

src/main/java/de/uapcore/lightpit/ModuleManager.java