1 /* 2 * Copyright (c) 2016, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.core.common.util; 24 25 import static org.graalvm.compiler.core.common.util.Util.JAVA_SPECIFICATION_VERSION; 26 27 import java.lang.reflect.InvocationTargetException; 28 import java.lang.reflect.Method; 29 import java.lang.reflect.Modifier; 30 31 /** 32 * Reflection based access to the Module API introduced by JDK 9. This allows the API to be used in 33 * code that must be compiled on a JDK prior to 9. Use of this class must be guarded by a test for 34 * JDK 9 or later. For example: 35 * 36 * <pre> 37 * if (Util.JAVA_SPECIFICATION_VERSION >= 9) { 38 * // Use of ModuleAPI 39 * } 40 * </pre> 41 */ 42 public final class ModuleAPI { 43 44 private ModuleAPI(Method method) { 45 this.method = method; 46 } 47 48 private final Method method; 49 50 /** 51 * {@code Class.getModule()}. 52 */ 53 public static final ModuleAPI getModule; 54 55 /** 56 * {@code jdk.internal.module.Modules.addExports(Module, String, Module)}. 57 */ 58 public static final ModuleAPI addExports; 59 60 /** 61 * {@code java.lang.reflect.Module.getResourceAsStream(String)}. 62 */ 63 public static final ModuleAPI getResourceAsStream; 64 65 /** 66 * {@code java.lang.reflect.Module.canRead(Module)}. 67 */ 68 public static final ModuleAPI canRead; 69 70 /** 71 * {@code java.lang.reflect.Module.isExported(String)}. 72 */ 73 public static final ModuleAPI isExported; 74 75 /** 76 * {@code java.lang.reflect.Module.isExported(String, Module)}. 77 */ 78 public static final ModuleAPI isExportedTo; 79 80 /** 81 * Invokes the static Module API method represented by this object. 82 */ 83 @SuppressWarnings("unchecked") 84 public <T> T invokeStatic(Object... args) { 85 checkAvailability(); 86 assert Modifier.isStatic(method.getModifiers()); 87 try { 88 return (T) method.invoke(null, args); 89 } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) { 90 throw new InternalError(e); 91 } 92 } 93 94 /** 95 * Invokes the non-static Module API method represented by this object. 96 */ 97 @SuppressWarnings("unchecked") 98 public <T> T invoke(Object receiver, Object... args) { 99 checkAvailability(); 100 assert !Modifier.isStatic(method.getModifiers()); 101 try { 102 return (T) method.invoke(receiver, args); 103 } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) { 104 throw new InternalError(e); 105 } 106 } 107 108 private void checkAvailability() throws InternalError { 109 if (method == null) { 110 throw new InternalError("Cannot use Module API on JDK " + JAVA_SPECIFICATION_VERSION); 111 } 112 } 113 114 static { 115 if (JAVA_SPECIFICATION_VERSION >= 9) { 116 try { 117 getModule = new ModuleAPI(Class.class.getMethod("getModule")); 118 Class<?> moduleClass = getModule.method.getReturnType(); 119 Class<?> modulesClass = Class.forName("jdk.internal.module.Modules"); 120 getResourceAsStream = new ModuleAPI(moduleClass.getMethod("getResourceAsStream", String.class)); 121 canRead = new ModuleAPI(moduleClass.getMethod("canRead", moduleClass)); 122 isExported = new ModuleAPI(moduleClass.getMethod("isExported", String.class)); 123 isExportedTo = new ModuleAPI(moduleClass.getMethod("isExported", String.class, moduleClass)); 124 addExports = new ModuleAPI(modulesClass.getDeclaredMethod("addExports", moduleClass, String.class, moduleClass)); 125 } catch (NoSuchMethodException | SecurityException | ClassNotFoundException e) { 126 throw new InternalError(e); 127 } 128 } else { 129 ModuleAPI unavailable = new ModuleAPI(null); 130 getModule = unavailable; 131 getResourceAsStream = unavailable; 132 canRead = unavailable; 133 isExported = unavailable; 134 isExportedTo = unavailable; 135 addExports = unavailable; 136 } 137 138 } 139 }