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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package java.lang;
     18 
     19 import java.io.File;
     20 import java.io.IOException;
     21 import java.net.URL;
     22 import java.net.URLStreamHandler;
     23 import java.util.ArrayList;
     24 import java.util.List;
     25 import libcore.io.ClassPathURLStreamHandler;
     26 
     27 class VMClassLoader {
     28 
     29     private static final ClassPathURLStreamHandler[] bootClassPathUrlHandlers;
     30     static {
     31         bootClassPathUrlHandlers = createBootClassPathUrlHandlers();
     32     }
     33 
     34     /**
     35      * Creates an array of ClassPathURLStreamHandler objects for handling resource loading from
     36      * the boot classpath.
     37      */
     38     private static ClassPathURLStreamHandler[] createBootClassPathUrlHandlers() {
     39         String[] bootClassPathEntries = getBootClassPathEntries();
     40         ArrayList<String> zipFileUris = new ArrayList<String>(bootClassPathEntries.length);
     41         ArrayList<URLStreamHandler> urlStreamHandlers =
     42                 new ArrayList<URLStreamHandler>(bootClassPathEntries.length);
     43         for (String bootClassPathEntry : bootClassPathEntries) {
     44             try {
     45                 String entryUri = new File(bootClassPathEntry).toURI().toString();
     46 
     47                 // We assume all entries are zip or jar files.
     48                 URLStreamHandler urlStreamHandler =
     49                         new ClassPathURLStreamHandler(bootClassPathEntry);
     50                 zipFileUris.add(entryUri);
     51                 urlStreamHandlers.add(urlStreamHandler);
     52             } catch (IOException e) {
     53                 // Skip it
     54                 System.logE("Unable to open boot classpath entry: " + bootClassPathEntry, e);
     55             }
     56         }
     57         return urlStreamHandlers.toArray(new ClassPathURLStreamHandler[urlStreamHandlers.size()]);
     58     }
     59 
     60     /**
     61      * Get a resource from a file in the bootstrap class path.
     62      *
     63      * We assume that the bootclasspath can't change once the VM has started.
     64      * This assumption seems to be supported by the spec.
     65      */
     66     static URL getResource(String name) {
     67         for (ClassPathURLStreamHandler urlHandler : bootClassPathUrlHandlers) {
     68             URL url = urlHandler.getEntryUrlOrNull(name);
     69             if (url != null) {
     70                 return url;
     71             }
     72         }
     73         return null;
     74     }
     75 
     76     /*
     77      * Get an enumeration with all matching resources.
     78      */
     79     static List<URL> getResources(String name) {
     80         ArrayList<URL> list = new ArrayList<URL>();
     81         for (ClassPathURLStreamHandler urlHandler : bootClassPathUrlHandlers) {
     82             URL url = urlHandler.getEntryUrlOrNull(name);
     83             if (url != null) {
     84                 list.add(url);
     85             }
     86         }
     87         return list;
     88     }
     89 
     90     native static Class findLoadedClass(ClassLoader cl, String name);
     91 
     92     /**
     93      * Boot class path manipulation, for getResources().
     94      */
     95     native private static String[] getBootClassPathEntries();
     96 
     97 }
     98