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 package jdk.internal.loader;
  26 
  27 import jdk.internal.module.Checks;
  28 
  29 /**
  30  * Helper class for Class#getResource, Module#getResourceAsStream, and other
  31  * methods that locate a resource in a module.
  32  */
  33 public final class ResourceHelper {
  34     private ResourceHelper() { }
  35 
  36     /**
  37      * Returns the <em>package name</em> for a resource.
  38      */
  39     public static String getPackageName(String name) {
  40         int index = name.lastIndexOf('/');
  41         if (index != -1) {
  42             return name.substring(0, index).replace("/", ".");
  43         } else {
  44             return "";
  45         }
  46     }
  47 
  48     /**
  49      * Returns true if the resource is a <em>simple resource</em> that can
  50      * never be encapsulated. Resources ending in "{@code .class}" or where
  51      * the package name is not a Java identifier are resources that can
  52      * never be encapsulated.
  53      */
  54     public static boolean isSimpleResource(String name) {
  55         int len = name.length();
  56         if (len > 6 && name.endsWith(".class")) {
  57             return true;
  58         }
  59         if (!Checks.isJavaIdentifier(getPackageName(name))) {
  60             return true;
  61         }
  62         return false;
  63     }
  64 }