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 
  26 package jdk.nashorn.internal.scripts;
  27 
  28 import 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  */
  43 final 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 }