src/main/java/de/uapcore/lightpit/ModuleManager.java@cc7f082c5ef3
src/main/java/de/uapcore/lightpit/ModuleManager.java
Wed, 13 May 2020 21:10:23 +0200
- author
- Mike Becker <universe@uap-core.de>
- date
- Wed, 13 May 2020 21:10:23 +0200
- changeset 45
- cc7f082c5ef3
- parent 36
- 0f4f8f255c32
- child 57
- 1262b5433644
- permissions
- -rw-r--r--
simplifies menu generation, adds submenus and removes VersionsModule (versions will be part of the ProjectsModule)
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;
31 import org.slf4j.Logger;
32 import org.slf4j.LoggerFactory;
34 import javax.servlet.Registration;
35 import javax.servlet.ServletContext;
36 import javax.servlet.ServletContextEvent;
37 import javax.servlet.ServletContextListener;
38 import javax.servlet.annotation.WebListener;
39 import java.util.ArrayList;
40 import java.util.Collections;
41 import java.util.List;
42 import java.util.Optional;
44 /**
45 * Scans registered servlets for LightPIT modules.
46 */
47 @WebListener
48 public final class ModuleManager implements ServletContextListener {
50 private static final Logger LOG = LoggerFactory.getLogger(ModuleManager.class);
52 /**
53 * The attribute name in the servlet context under which an instance of this class can be found.
54 */
55 public static final String SC_ATTR_NAME = ModuleManager.class.getName();
56 private ServletContext sc;
58 /**
59 * Maps class names to module information.
60 */
61 private final List<LightPITModule> registeredModules = new ArrayList<>();
63 /**
64 * Contains the menu entries for the loaded modules.
65 */
66 private final List<MenuEntry> mainMenu = new ArrayList<>();
68 @Override
69 public void contextInitialized(ServletContextEvent sce) {
70 sc = sce.getServletContext();
71 reloadAll();
72 sc.setAttribute(SC_ATTR_NAME, this);
73 LOG.info("Module manager injected into ServletContext.");
74 }
76 @Override
77 public void contextDestroyed(ServletContextEvent sce) {
78 unloadAll();
79 }
81 private Optional<LightPITModule> getModuleInfo(Registration reg) {
82 try {
83 final Class<?> scclass = Class.forName(reg.getClassName());
85 final boolean lpservlet = AbstractLightPITServlet.class.isAssignableFrom(scclass);
86 final boolean lpmodule = scclass.isAnnotationPresent(LightPITModule.class);
88 if (lpservlet && !lpmodule) {
89 LOG.warn(
90 "{} is a LightPIT Servlet but is missing the module annotation.",
91 reg.getClassName()
92 );
93 } else if (!lpservlet && lpmodule) {
94 LOG.warn(
95 "{} is annotated as a LightPIT Module but does not extend {}.",
96 reg.getClassName(),
97 AbstractLightPITServlet.class.getSimpleName()
98 );
99 }
101 if (lpservlet && lpmodule) {
102 final LightPITModule moduleInfo = scclass.getAnnotation(LightPITModule.class);
103 return Optional.of(moduleInfo);
104 } else {
105 return Optional.empty();
106 }
107 } catch (ClassNotFoundException ex) {
108 LOG.error(
109 "Servlet registration refers to class {} which cannot be found by the class loader (Reason: {})",
110 reg.getClassName(),
111 ex.getMessage()
112 );
113 return Optional.empty();
114 }
115 }
117 private void handleServletRegistration(String name, Registration reg) {
118 final Optional<LightPITModule> moduleInfo = getModuleInfo(reg);
119 if (moduleInfo.isPresent()) {
120 registeredModules.add(moduleInfo.get());
121 LOG.info("Module detected: {}", name);
122 } else {
123 LOG.debug("Servlet {} is no module, skipping.", name);
124 }
125 }
127 /**
128 * Scans for modules and reloads them all.
129 */
130 public void reloadAll() {
131 registeredModules.clear();
132 sc.getServletRegistrations().forEach(this::handleServletRegistration);
133 createMainMenu();
135 LOG.info("Modules loaded.");
136 }
138 /**
139 * Unloads all found modules.
140 */
141 public void unloadAll() {
142 registeredModules.clear();
143 LOG.info("All modules unloaded.");
144 }
146 /**
147 * Populates the main menu based on the registered modules.
148 */
149 private void createMainMenu() {
150 mainMenu.clear();
151 registeredModules
152 .stream()
153 .filter(mod -> !mod.systemModule())
154 .map(mod -> new MenuEntry(
155 new ResourceKey(
156 mod.bundleBaseName(),
157 mod.menuKey()),
158 mod.modulePath(),
159 mod.defaultPriority()))
160 .sorted()
161 .forEachOrdered(mainMenu::add);
162 }
164 /**
165 * Returns the main menu.
166 *
167 * @return a list of menu items
168 */
169 public List<MenuEntry> getMainMenu() {
170 return Collections.unmodifiableList(mainMenu);
171 }
172 }
