1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/main/java/de/uapcore/lightpit/ModuleManager.java Sat May 09 14:26:31 2020 +0200
1.3 @@ -0,0 +1,231 @@
1.4 +/*
1.5 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 + *
1.7 + * Copyright 2018 Mike Becker. All rights reserved.
1.8 + *
1.9 + * Redistribution and use in source and binary forms, with or without
1.10 + * modification, are permitted provided that the following conditions are met:
1.11 + *
1.12 + * 1. Redistributions of source code must retain the above copyright
1.13 + * notice, this list of conditions and the following disclaimer.
1.14 + *
1.15 + * 2. Redistributions in binary form must reproduce the above copyright
1.16 + * notice, this list of conditions and the following disclaimer in the
1.17 + * documentation and/or other materials provided with the distribution.
1.18 + *
1.19 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.20 + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.21 + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.22 + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
1.23 + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.24 + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.25 + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.26 + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.27 + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.28 + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.29 + * POSSIBILITY OF SUCH DAMAGE.
1.30 + *
1.31 + */
1.32 +package de.uapcore.lightpit;
1.33 +
1.34 +import de.uapcore.lightpit.entities.CoreDAOFactory;
1.35 +import de.uapcore.lightpit.entities.Module;
1.36 +import de.uapcore.lightpit.entities.ModuleDao;
1.37 +import java.sql.Connection;
1.38 +import java.sql.SQLException;
1.39 +import java.util.Collections;
1.40 +import java.util.HashMap;
1.41 +import java.util.List;
1.42 +import java.util.Map;
1.43 +import java.util.Optional;
1.44 +import java.util.concurrent.atomic.AtomicBoolean;
1.45 +import java.util.stream.Collectors;
1.46 +import javax.servlet.Registration;
1.47 +import javax.servlet.ServletContext;
1.48 +import javax.servlet.ServletContextEvent;
1.49 +import javax.servlet.ServletContextListener;
1.50 +import javax.servlet.annotation.WebListener;
1.51 +import org.slf4j.Logger;
1.52 +import org.slf4j.LoggerFactory;
1.53 +
1.54 +/**
1.55 + * Scans registered servlets for LightPIT modules.
1.56 + */
1.57 +@WebListener
1.58 +public final class ModuleManager implements ServletContextListener {
1.59 +
1.60 + private static final Logger LOG = LoggerFactory.getLogger(ModuleManager.class);
1.61 +
1.62 + /**
1.63 + * The attribute name in the servlet context under which an instance of this class can be found.
1.64 + */
1.65 + public static final String SC_ATTR_NAME = ModuleManager.class.getName();
1.66 + private ServletContext sc;
1.67 +
1.68 + /**
1.69 + * Maps class names to module information.
1.70 + */
1.71 + private final Map<String, LightPITModule> registeredModules = new HashMap<>();
1.72 +
1.73 + /**
1.74 + * This flag is true, when synchronization is needed.
1.75 + */
1.76 + private final AtomicBoolean dirty = new AtomicBoolean(true);
1.77 +
1.78 + @Override
1.79 + public void contextInitialized(ServletContextEvent sce) {
1.80 + sc = sce.getServletContext();
1.81 + reloadAll();
1.82 + sc.setAttribute(SC_ATTR_NAME, this);
1.83 + LOG.info("Module manager injected into ServletContext.");
1.84 + }
1.85 +
1.86 + @Override
1.87 + public void contextDestroyed(ServletContextEvent sce) {
1.88 + unloadAll();
1.89 + }
1.90 +
1.91 + private Optional<LightPITModule> getModuleInfo(Registration reg) {
1.92 + try {
1.93 + final Class scclass = Class.forName(reg.getClassName());
1.94 +
1.95 + final boolean lpservlet = AbstractLightPITServlet.class.isAssignableFrom(scclass);
1.96 + final boolean lpmodule = scclass.isAnnotationPresent(LightPITModule.class);
1.97 +
1.98 + if (lpservlet && !lpmodule) {
1.99 + LOG.warn(
1.100 + "{} is a LightPIT Servlet but is missing the module annotation.",
1.101 + reg.getClassName()
1.102 + );
1.103 + } else if (!lpservlet && lpmodule) {
1.104 + LOG.warn(
1.105 + "{} is annotated as a LightPIT Module but does not extend {}.",
1.106 + reg.getClassName(),
1.107 + AbstractLightPITServlet.class.getSimpleName()
1.108 + );
1.109 + }
1.110 +
1.111 + if (lpservlet && lpmodule) {
1.112 + final Class<? extends AbstractLightPITServlet> clazz = scclass;
1.113 + final LightPITModule moduleInfo = clazz.getAnnotation(LightPITModule.class);
1.114 + return Optional.of(moduleInfo);
1.115 + } else {
1.116 + return Optional.empty();
1.117 + }
1.118 + } catch (ClassNotFoundException ex) {
1.119 + LOG.error(
1.120 + "Servlet registration refers to class {} which cannot be found by the class loader (Reason: {})",
1.121 + reg.getClassName(),
1.122 + ex.getMessage()
1.123 + );
1.124 + return Optional.empty();
1.125 + }
1.126 + }
1.127 +
1.128 + private void handleServletRegistration(String name, Registration reg) {
1.129 + final Optional<LightPITModule> moduleInfo = getModuleInfo(reg);
1.130 + if (moduleInfo.isPresent()) {
1.131 + registeredModules.put(reg.getClassName(), moduleInfo.get());
1.132 + LOG.info("Module detected: {}", name);
1.133 + } else {
1.134 + LOG.debug("Servlet {} is no module, skipping.", name);
1.135 + }
1.136 + }
1.137 +
1.138 + /**
1.139 + * Scans for modules and reloads them all.
1.140 + */
1.141 + public void reloadAll() {
1.142 + registeredModules.clear();
1.143 + sc.getServletRegistrations().forEach(this::handleServletRegistration);
1.144 +
1.145 + // TODO: implement dependency resolver
1.146 +
1.147 + dirty.set(true);
1.148 + LOG.info("Modules loaded.");
1.149 + }
1.150 +
1.151 + /**
1.152 + * Synchronizes module information with the database.
1.153 + *
1.154 + * This must be called from the {@link AbstractLightPITServlet}.
1.155 + * Admittedly the call will perform the synchronization once after reload
1.156 + * and be a no-op, afterwards.
1.157 + * However, we since the DatabaseFacade might be loaded after the module
1.158 + * manager, we must defer the synchronization to the first request
1.159 + * handled by the Servlet.
1.160 + *
1.161 + * @param db interface to the database
1.162 + */
1.163 + public void syncWithDatabase(DatabaseFacade db) {
1.164 + if (dirty.compareAndSet(true, false)) {
1.165 + if (db.getDataSource().isPresent()) {
1.166 + try (Connection conn = db.getDataSource().get().getConnection()) {
1.167 + final ModuleDao moduleDao = CoreDAOFactory.getModuleDao(db.getSQLDialect());
1.168 + moduleDao.syncRegisteredModuleClasses(conn, registeredModules.entrySet());
1.169 + } catch (SQLException ex) {
1.170 + LOG.error("Unexpected SQL Exception", ex);
1.171 + }
1.172 + } else {
1.173 + LOG.error("No datasource present. Cannot sync module information with database.");
1.174 + }
1.175 + } else {
1.176 + LOG.trace("Module information clean - no synchronization required.");
1.177 + }
1.178 + }
1.179 +
1.180 + /**
1.181 + * Unloads all found modules.
1.182 + */
1.183 + public void unloadAll() {
1.184 + registeredModules.clear();
1.185 + LOG.info("All modules unloaded.");
1.186 + }
1.187 +
1.188 + /**
1.189 + * Returns the main menu.
1.190 + *
1.191 + * @param db the interface to the database
1.192 + * @return a list of menus belonging to the main menu
1.193 + */
1.194 + public List<Menu> getMainMenu(DatabaseFacade db) {
1.195 + // TODO: user specific menu
1.196 +
1.197 + if (db.getDataSource().isPresent()) {
1.198 + try (Connection conn = db.getDataSource().get().getConnection()) {
1.199 + final ModuleDao dao = CoreDAOFactory.getModuleDao(db.getSQLDialect());
1.200 + final List<Module> modules = dao.listAll(conn);
1.201 +
1.202 + final List<Menu> menu = modules
1.203 + .stream()
1.204 + .filter((mod) -> mod.isVisible())
1.205 + .collect(Collectors.mapping(
1.206 + (mod) -> new Menu(
1.207 + mod.getClassname(),
1.208 + new ResourceKey(
1.209 + registeredModules.get(mod.getClassname()).bundleBaseName(),
1.210 + registeredModules.get(mod.getClassname()).menuKey()),
1.211 + registeredModules.get(mod.getClassname()).modulePath()),
1.212 + Collectors.toList())
1.213 + );
1.214 + return menu;
1.215 + } catch (SQLException ex) {
1.216 + LOG.error("Unexpected SQLException when loading the main menu", ex);
1.217 + return Collections.emptyList();
1.218 + }
1.219 + } else {
1.220 + return Collections.emptyList();
1.221 + }
1.222 + }
1.223 +
1.224 + /**
1.225 + * Returns an unmodifiable map of all registered modules.
1.226 + *
1.227 + * The key is the classname of the module.
1.228 + *
1.229 + * @return the map of registered modules
1.230 + */
1.231 + public Map<String, LightPITModule> getRegisteredModules() {
1.232 + return Collections.unmodifiableMap(registeredModules);
1.233 + }
1.234 +}
