ModuleGraphManipulator.java revision 1894:48d8835e3aaa 
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.  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
26package jdk.nashorn.internal.scripts;
27
28import jdk.nashorn.api.scripting.JSObject;
29
30/**
31 * Nashorn's StructureLoader and ScriptLoader instances load
32 * this class in the respective dynamic modules created. This
33 * class is never loaded by Nashorn's own class loader. The
34 * .class bytes of this class are loaded as resource by the
35 * {@link jdk.nashorn.internal.runtime.NashornLoader} class. This class
36 * exists in this package because nashorn structures and scripts
37 * modules use this package name for the only exported package
38 * from those modules.
39 *
40 * Note that this class may be dynamically generated at runtime.
41 * But, this java source is used for ease of reading.
42 */
43final class ModuleGraphManipulator {
44    private ModuleGraphManipulator() {}
45
46    private static final Module MY_MODULE;
47    private static final String MY_PKG_NAME;
48
49    static {
50        final Class<?> myClass = ModuleGraphManipulator.class;
51        MY_MODULE = myClass.getModule();
52        final String myName = myClass.getName();
53        MY_PKG_NAME = myName.substring(0, myName.lastIndexOf('.'));
54
55        // nashorn's module is the module of the class loader of current class
56        final Module nashornModule = myClass.getClassLoader().getClass().getModule();
57
58        // Make sure this class was not loaded by Nashorn's own loader!
59        if (MY_MODULE == nashornModule) {
60            throw new IllegalStateException(myClass + " loaded by wrong loader!");
61        }
62
63        // open package to nashorn module
64        MY_MODULE.addOpens(MY_PKG_NAME, nashornModule);
65    }
66
67    // The following method is reflectively invoked from Nashorn
68    // to add required module export edges. Because this package
69    // itself is qualified exported only to nashorn and this
70    // method is private, unsafe calls are not possible.
71
72    private static void addExport(final Module otherMod) {
73        MY_MODULE.addExports(MY_PKG_NAME, otherMod);
74    }
75}
76