comparison: src/java/de/uapcore/lightpit/ModuleManager.java
src/java/de/uapcore/lightpit/ModuleManager.java
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- 27a0fdd7bca7
- parent 27
- 1f2a96efa69f
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| 1 /* | |
| 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. | |
| 3 * | |
| 4 * Copyright 2018 Mike Becker. All rights reserved. | |
| 5 * | |
| 6 * Redistribution and use in source and binary forms, with or without | |
| 7 * modification, are permitted provided that the following conditions are met: | |
| 8 * | |
| 9 * 1. Redistributions of source code must retain the above copyright | |
| 10 * notice, this list of conditions and the following disclaimer. | |
| 11 * | |
| 12 * 2. Redistributions in binary form must reproduce the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer in the | |
| 14 * documentation and/or other materials provided with the distribution. | |
| 15 * | |
| 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | |
| 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 26 * POSSIBILITY OF SUCH DAMAGE. | |
| 27 * | |
| 28 */ | |
| 29 package de.uapcore.lightpit; | |
| 30 | |
| 31 import de.uapcore.lightpit.entities.CoreDAOFactory; | |
| 32 import de.uapcore.lightpit.entities.Module; | |
| 33 import de.uapcore.lightpit.entities.ModuleDao; | |
| 34 import java.sql.Connection; | |
| 35 import java.sql.SQLException; | |
| 36 import java.util.Collections; | |
| 37 import java.util.HashMap; | |
| 38 import java.util.List; | |
| 39 import java.util.Map; | |
| 40 import java.util.Optional; | |
| 41 import java.util.concurrent.atomic.AtomicBoolean; | |
| 42 import java.util.stream.Collectors; | |
| 43 import javax.servlet.Registration; | |
| 44 import javax.servlet.ServletContext; | |
| 45 import javax.servlet.ServletContextEvent; | |
| 46 import javax.servlet.ServletContextListener; | |
| 47 import javax.servlet.annotation.WebListener; | |
| 48 import org.slf4j.Logger; | |
| 49 import org.slf4j.LoggerFactory; | |
| 50 | |
| 51 /** | |
| 52 * Scans registered servlets for LightPIT modules. | |
| 53 */ | |
| 54 @WebListener | |
| 55 public final class ModuleManager implements ServletContextListener { | |
| 56 | |
| 57 private static final Logger LOG = LoggerFactory.getLogger(ModuleManager.class); | |
| 58 | |
| 59 /** | |
| 60 * The attribute name in the servlet context under which an instance of this class can be found. | |
| 61 */ | |
| 62 public static final String SC_ATTR_NAME = ModuleManager.class.getName(); | |
| 63 private ServletContext sc; | |
| 64 | |
| 65 /** | |
| 66 * Maps class names to module information. | |
| 67 */ | |
| 68 private final Map<String, LightPITModule> registeredModules = new HashMap<>(); | |
| 69 | |
| 70 /** | |
| 71 * This flag is true, when synchronization is needed. | |
| 72 */ | |
| 73 private final AtomicBoolean dirty = new AtomicBoolean(true); | |
| 74 | |
| 75 @Override | |
| 76 public void contextInitialized(ServletContextEvent sce) { | |
| 77 sc = sce.getServletContext(); | |
| 78 reloadAll(); | |
| 79 sc.setAttribute(SC_ATTR_NAME, this); | |
| 80 LOG.info("Module manager injected into ServletContext."); | |
| 81 } | |
| 82 | |
| 83 @Override | |
| 84 public void contextDestroyed(ServletContextEvent sce) { | |
| 85 unloadAll(); | |
| 86 } | |
| 87 | |
| 88 private Optional<LightPITModule> getModuleInfo(Registration reg) { | |
| 89 try { | |
| 90 final Class scclass = Class.forName(reg.getClassName()); | |
| 91 | |
| 92 final boolean lpservlet = AbstractLightPITServlet.class.isAssignableFrom(scclass); | |
| 93 final boolean lpmodule = scclass.isAnnotationPresent(LightPITModule.class); | |
| 94 | |
| 95 if (lpservlet && !lpmodule) { | |
| 96 LOG.warn( | |
| 97 "{} is a LightPIT Servlet but is missing the module annotation.", | |
| 98 reg.getClassName() | |
| 99 ); | |
| 100 } else if (!lpservlet && lpmodule) { | |
| 101 LOG.warn( | |
| 102 "{} is annotated as a LightPIT Module but does not extend {}.", | |
| 103 reg.getClassName(), | |
| 104 AbstractLightPITServlet.class.getSimpleName() | |
| 105 ); | |
| 106 } | |
| 107 | |
| 108 if (lpservlet && lpmodule) { | |
| 109 final Class<? extends AbstractLightPITServlet> clazz = scclass; | |
| 110 final LightPITModule moduleInfo = clazz.getAnnotation(LightPITModule.class); | |
| 111 return Optional.of(moduleInfo); | |
| 112 } else { | |
| 113 return Optional.empty(); | |
| 114 } | |
| 115 } catch (ClassNotFoundException ex) { | |
| 116 LOG.error( | |
| 117 "Servlet registration refers to class {} which cannot be found by the class loader (Reason: {})", | |
| 118 reg.getClassName(), | |
| 119 ex.getMessage() | |
| 120 ); | |
| 121 return Optional.empty(); | |
| 122 } | |
| 123 } | |
| 124 | |
| 125 private void handleServletRegistration(String name, Registration reg) { | |
| 126 final Optional<LightPITModule> moduleInfo = getModuleInfo(reg); | |
| 127 if (moduleInfo.isPresent()) { | |
| 128 registeredModules.put(reg.getClassName(), moduleInfo.get()); | |
| 129 LOG.info("Module detected: {}", name); | |
| 130 } else { | |
| 131 LOG.debug("Servlet {} is no module, skipping.", name); | |
| 132 } | |
| 133 } | |
| 134 | |
| 135 /** | |
| 136 * Scans for modules and reloads them all. | |
| 137 */ | |
| 138 public void reloadAll() { | |
| 139 registeredModules.clear(); | |
| 140 sc.getServletRegistrations().forEach(this::handleServletRegistration); | |
| 141 | |
| 142 // TODO: implement dependency resolver | |
| 143 | |
| 144 dirty.set(true); | |
| 145 LOG.info("Modules loaded."); | |
| 146 } | |
| 147 | |
| 148 /** | |
| 149 * Synchronizes module information with the database. | |
| 150 * | |
| 151 * This must be called from the {@link AbstractLightPITServlet}. | |
| 152 * Admittedly the call will perform the synchronization once after reload | |
| 153 * and be a no-op, afterwards. | |
| 154 * However, we since the DatabaseFacade might be loaded after the module | |
| 155 * manager, we must defer the synchronization to the first request | |
| 156 * handled by the Servlet. | |
| 157 * | |
| 158 * @param db interface to the database | |
| 159 */ | |
| 160 public void syncWithDatabase(DatabaseFacade db) { | |
| 161 if (dirty.compareAndSet(true, false)) { | |
| 162 if (db.getDataSource().isPresent()) { | |
| 163 try (Connection conn = db.getDataSource().get().getConnection()) { | |
| 164 final ModuleDao moduleDao = CoreDAOFactory.getModuleDao(db.getSQLDialect()); | |
| 165 moduleDao.syncRegisteredModuleClasses(conn, registeredModules.entrySet()); | |
| 166 } catch (SQLException ex) { | |
| 167 LOG.error("Unexpected SQL Exception", ex); | |
| 168 } | |
| 169 } else { | |
| 170 LOG.error("No datasource present. Cannot sync module information with database."); | |
| 171 } | |
| 172 } else { | |
| 173 LOG.trace("Module information clean - no synchronization required."); | |
| 174 } | |
| 175 } | |
| 176 | |
| 177 /** | |
| 178 * Unloads all found modules. | |
| 179 */ | |
| 180 public void unloadAll() { | |
| 181 registeredModules.clear(); | |
| 182 LOG.info("All modules unloaded."); | |
| 183 } | |
| 184 | |
| 185 /** | |
| 186 * Returns the main menu. | |
| 187 * | |
| 188 * @param db the interface to the database | |
| 189 * @return a list of menus belonging to the main menu | |
| 190 */ | |
| 191 public List<Menu> getMainMenu(DatabaseFacade db) { | |
| 192 // TODO: user specific menu | |
| 193 | |
| 194 if (db.getDataSource().isPresent()) { | |
| 195 try (Connection conn = db.getDataSource().get().getConnection()) { | |
| 196 final ModuleDao dao = CoreDAOFactory.getModuleDao(db.getSQLDialect()); | |
| 197 final List<Module> modules = dao.listAll(conn); | |
| 198 | |
| 199 final List<Menu> menu = modules | |
| 200 .stream() | |
| 201 .filter((mod) -> mod.isVisible()) | |
| 202 .collect(Collectors.mapping( | |
| 203 (mod) -> new Menu( | |
| 204 mod.getClassname(), | |
| 205 new ResourceKey( | |
| 206 registeredModules.get(mod.getClassname()).bundleBaseName(), | |
| 207 registeredModules.get(mod.getClassname()).menuKey()), | |
| 208 registeredModules.get(mod.getClassname()).modulePath()), | |
| 209 Collectors.toList()) | |
| 210 ); | |
| 211 return menu; | |
| 212 } catch (SQLException ex) { | |
| 213 LOG.error("Unexpected SQLException when loading the main menu", ex); | |
| 214 return Collections.emptyList(); | |
| 215 } | |
| 216 } else { | |
| 217 return Collections.emptyList(); | |
| 218 } | |
| 219 } | |
| 220 | |
| 221 /** | |
| 222 * Returns an unmodifiable map of all registered modules. | |
| 223 * | |
| 224 * The key is the classname of the module. | |
| 225 * | |
| 226 * @return the map of registered modules | |
| 227 */ | |
| 228 public Map<String, LightPITModule> getRegisteredModules() { | |
| 229 return Collections.unmodifiableMap(registeredModules); | |
| 230 } | |
| 231 } |
