1 /*
2  * Copyright (c) 2015, 2017, 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.HashSet;
32 import java.util.Map;
33 import java.util.Set;
34 import java.util.function.Function;
35 
36 import jdk.internal.loader.ClassLoaders;
37 
38 
39 /**
40  * Supports the mapping of modules to class loaders. The set of modules mapped
41  * to the boot and platform class loaders is generated at build time from
42  * this source file.
43  */
44 public final class ModuleLoaderMap {
45 
46     /**
47      * Maps the system modules to the built-in class loaders.
48      */
49     public static final class Mapper implements Function<String, ClassLoader> {
50         private final Map<String, ClassLoader> map;
51 
Mapper(Map<String, ClassLoader> map)52         Mapper(Map<String, ClassLoader> map) {
53             this.map = map; // defensive copy not needed
54         }
55 
56         @Override
apply(String name)57         public ClassLoader apply(String name) {
58             return map.get(name);
59         }
60     }
61 
62     /**
63      * Returns the names of the modules defined to the boot loader.
64      */
bootModules()65     public static Set<String> bootModules() {
66         // The list of boot modules generated at build time.
67         String[] BOOT_MODULES = new String[] { "@@BOOT_MODULE_NAMES@@" };
68         Set<String> bootModules = new HashSet<>(BOOT_MODULES.length);
69         for (String mn : BOOT_MODULES) {
70             bootModules.add(mn);
71         }
72         return bootModules;
73     }
74 
75     /**
76      * Returns the names of the modules defined to the platform loader.
77      */
platformModules()78     public static Set<String> platformModules() {
79         // The list of platform modules generated at build time.
80         String[] PLATFORM_MODULES = new String[] { "@@PLATFORM_MODULE_NAMES@@" };
81         Set<String> platformModules = new HashSet<>(PLATFORM_MODULES.length);
82         for (String mn : PLATFORM_MODULES) {
83             platformModules.add(mn);
84         }
85         return platformModules;
86     }
87 
88     /**
89      * Returns the function to map modules in the given configuration to the
90      * built-in class loaders.
91      */
mappingFunction(Configuration cf)92     static Function<String, ClassLoader> mappingFunction(Configuration cf) {
93         Set<String> bootModules = bootModules();
94         Set<String> platformModules = platformModules();
95 
96         ClassLoader platformClassLoader = ClassLoaders.platformClassLoader();
97         ClassLoader appClassLoader = ClassLoaders.appClassLoader();
98 
99         Map<String, ClassLoader> map = new HashMap<>();
100         for (ResolvedModule resolvedModule : cf.modules()) {
101             String mn = resolvedModule.name();
102             if (!bootModules.contains(mn)) {
103                 if (platformModules.contains(mn)) {
104                     map.put(mn, platformClassLoader);
105                 } else {
106                     map.put(mn, appClassLoader);
107                 }
108             }
109         }
110         return new Mapper(map);
111     }
112 }
113