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 
  52         Mapper(Map<String, ClassLoader> map) {
  53             this.map = map; // defensive copy not needed
  54         }
  55 
  56         @Override
  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      */
  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      */
  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      */
  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 }