src/main/java/de/uapcore/lightpit/ModuleManager.java@4f1c026a8aab
src/main/java/de/uapcore/lightpit/ModuleManager.java
Wed, 13 May 2020 18:33:25 +0200
- author
- Mike Becker <universe@uap-core.de>
- date
- Wed, 13 May 2020 18:33:25 +0200
- changeset 41
- 4f1c026a8aab
- parent 36
- 0f4f8f255c32
- child 45
- cc7f082c5ef3
- permissions
- -rw-r--r--
adds files for 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.*;
41 /**
42 * Scans registered servlets for LightPIT modules.
43 */
44 @WebListener
45 public final class ModuleManager implements ServletContextListener {
47 private static final Logger LOG = LoggerFactory.getLogger(ModuleManager.class);
49 /**
50 * The attribute name in the servlet context under which an instance of this class can be found.
51 */
52 public static final String SC_ATTR_NAME = ModuleManager.class.getName();
53 private ServletContext sc;
55 /**
56 * Maps class names to module information.
57 */
58 private final Map<String, LightPITModule> registeredModules = new HashMap<>();
60 /**
61 * Contains the menu entries for the loaded modules.
62 */
63 private final List<MenuEntry> mainMenu = new ArrayList<>();
65 @Override
66 public void contextInitialized(ServletContextEvent sce) {
67 sc = sce.getServletContext();
68 reloadAll();
69 sc.setAttribute(SC_ATTR_NAME, this);
70 LOG.info("Module manager injected into ServletContext.");
71 }
73 @Override
74 public void contextDestroyed(ServletContextEvent sce) {
75 unloadAll();
76 }
78 private Optional<LightPITModule> getModuleInfo(Registration reg) {
79 try {
80 final Class<?> scclass = Class.forName(reg.getClassName());
82 final boolean lpservlet = AbstractLightPITServlet.class.isAssignableFrom(scclass);
83 final boolean lpmodule = scclass.isAnnotationPresent(LightPITModule.class);
85 if (lpservlet && !lpmodule) {
86 LOG.warn(
87 "{} is a LightPIT Servlet but is missing the module annotation.",
88 reg.getClassName()
89 );
90 } else if (!lpservlet && lpmodule) {
91 LOG.warn(
92 "{} is annotated as a LightPIT Module but does not extend {}.",
93 reg.getClassName(),
94 AbstractLightPITServlet.class.getSimpleName()
95 );
96 }
98 if (lpservlet && lpmodule) {
99 final LightPITModule moduleInfo = scclass.getAnnotation(LightPITModule.class);
100 return Optional.of(moduleInfo);
101 } else {
102 return Optional.empty();
103 }
104 } catch (ClassNotFoundException ex) {
105 LOG.error(
106 "Servlet registration refers to class {} which cannot be found by the class loader (Reason: {})",
107 reg.getClassName(),
108 ex.getMessage()
109 );
110 return Optional.empty();
111 }
112 }
114 private void handleServletRegistration(String name, Registration reg) {
115 final Optional<LightPITModule> moduleInfo = getModuleInfo(reg);
116 if (moduleInfo.isPresent()) {
117 registeredModules.put(reg.getClassName(), moduleInfo.get());
118 LOG.info("Module detected: {}", name);
119 } else {
120 LOG.debug("Servlet {} is no module, skipping.", name);
121 }
122 }
124 /**
125 * Scans for modules and reloads them all.
126 */
127 public void reloadAll() {
128 registeredModules.clear();
129 sc.getServletRegistrations().forEach(this::handleServletRegistration);
130 createMainMenu();
132 LOG.info("Modules loaded.");
133 }
135 /**
136 * Unloads all found modules.
137 */
138 public void unloadAll() {
139 registeredModules.clear();
140 LOG.info("All modules unloaded.");
141 }
143 /**
144 * Populates the main menu based on the registered modules.
145 */
146 private void createMainMenu() {
147 mainMenu.clear();
148 registeredModules.entrySet()
149 .stream()
150 .filter(mod -> !mod.getValue().systemModule())
151 .map(mod -> new MenuEntry(
152 mod.getKey(),
153 new ResourceKey(
154 mod.getValue().bundleBaseName(),
155 mod.getValue().menuKey()),
156 mod.getValue().modulePath(),
157 mod.getValue().defaultPriority()))
158 .sorted()
159 .forEachOrdered(mainMenu::add);
160 }
162 /**
163 * Returns the main menu.
164 *
165 * @return a list of menu items
166 */
167 public List<MenuEntry> getMainMenu() {
168 return Collections.unmodifiableList(mainMenu);
169 }
170 }
