1 /*
2 * Copyright (c) 2015, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.module;
27
28 import java.lang.module.Configuration;
29 import java.lang.module.ResolvedModule;
30 import java.util.HashMap;
31 import java.util.Map;
32 import java.util.Set;
33 import java.util.function.Function;
34
35 import jdk.internal.loader.ClassLoaders;
36
37 /**
38 * Supports the mapping of modules to class loaders. The set of modules mapped
39 * to the boot and platform class loaders is generated at build time from
40 * this source file.
41 */
42 public final class ModuleLoaderMap {
43
44 /**
45 * Maps the system modules to the built-in class loaders.
46 */
47 private static final class Mapper implements Function<String, ClassLoader> {
48
49 private static final ClassLoader PLATFORM_CLASSLOADER =
50 ClassLoaders.platformClassLoader();
51 private static final ClassLoader APP_CLASSLOADER =
52 ClassLoaders.appClassLoader();
53
54 private static final Integer PLATFORM_LOADER_INDEX = 1;
55 private static final Integer APP_LOADER_INDEX = 2;
56
57 /**
58 * Map from module to a class loader index. The index is resolved to the
59 * actual class loader in {@code apply}.
60 */
61 private final Map<String, Integer> map;
62
63 /**
64 * Creates a Mapper to map module names in the given Configuration to
65 * built-in classloaders.
66 *
67 * As a proxy for the actual classloader, we store an easily archiveable
68 * index value in the internal map. The index is stored as a boxed value
69 * so that we can cheaply do identity comparisons during bootstrap.
70 */
71 Mapper(Configuration cf) {
72 var map = new HashMap<String, Integer>();
73 for (ResolvedModule resolvedModule : cf.modules()) {
74 String mn = resolvedModule.name();
75 if (!Modules.bootModules.contains(mn)) {
76 if (Modules.platformModules.contains(mn)) {
77 map.put(mn, PLATFORM_LOADER_INDEX);
78 } else {
79 map.put(mn, APP_LOADER_INDEX);
80 }
81 }
82 }
83 this.map = map;
84 }
85
86 @Override
87 public ClassLoader apply(String name) {
88 Integer loader = map.get(name);
89 if (loader == APP_LOADER_INDEX) {
90 return APP_CLASSLOADER;
91 } else if (loader == PLATFORM_LOADER_INDEX) {
92 return PLATFORM_CLASSLOADER;
93 } else { // BOOT_LOADER_INDEX
94 return null;
95 }
96 }
97 }
98
99 /**
100 * Returns the names of the modules defined to the boot loader.
101 */
102 public static Set<String> bootModules() {
103 return Modules.bootModules;
104 }
105
106 /**
107 * Returns the names of the modules defined to the platform loader.
108 */
109 public static Set<String> platformModules() {
110 return Modules.platformModules;
111 }
112
113 /**
114 * Returns the names of the modules defined to the application loader which perform native access.
115 */
116 public static Set<String> nativeAccessModules() {
117 return Modules.nativeAccessModules;
118 }
119
120 private static class Modules {
121 // list of boot modules is generated at build time.
122 private static final Set<String> bootModules =
123 Set.of(new String[] { "@@BOOT_MODULE_NAMES@@" });
124
125 // list of platform modules is generated at build time.
126 private static final Set<String> platformModules =
127 Set.of(new String[] { "@@PLATFORM_MODULE_NAMES@@" });
128
129 // list of jdk modules is generated at build time.
130 private static final Set<String> nativeAccessModules =
131 Set.of(new String[] { "@@NATIVE_ACCESS_MODULE_NAMES@@" });
132 }
133
134 /**
135 * Returns a function to map modules in the given configuration to the
136 * built-in class loaders.
137 */
138 static Function<String, ClassLoader> mappingFunction(Configuration cf) {
139 return new Mapper(cf);
140 }
141
142 /**
143 * When defining modules for a configuration, we only allow defining modules
144 * to the boot or platform classloader if the ClassLoader mapping function
145 * originate from here.
146 */
147 public static boolean isBuiltinMapper(Function<String, ClassLoader> clf) {
148 return clf instanceof Mapper;
149 }
150 }