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      1 /*
      2  * Copyright (C) 2006 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 android.app;
     18 
     19 import dalvik.system.PathClassLoader;
     20 
     21 import java.util.HashMap;
     22 import java.util.Map;
     23 
     24 class ApplicationLoaders
     25 {
     26     public static ApplicationLoaders getDefault()
     27     {
     28         return gApplicationLoaders;
     29     }
     30 
     31     public ClassLoader getClassLoader(String zip, String libPath, ClassLoader parent)
     32     {
     33         /*
     34          * This is the parent we use if they pass "null" in.  In theory
     35          * this should be the "system" class loader; in practice we
     36          * don't use that and can happily (and more efficiently) use the
     37          * bootstrap class loader.
     38          */
     39         ClassLoader baseParent = ClassLoader.getSystemClassLoader().getParent();
     40 
     41         synchronized (mLoaders) {
     42             if (parent == null) {
     43                 parent = baseParent;
     44             }
     45 
     46             /*
     47              * If we're one step up from the base class loader, find
     48              * something in our cache.  Otherwise, we create a whole
     49              * new ClassLoader for the zip archive.
     50              */
     51             if (parent == baseParent) {
     52                 ClassLoader loader = mLoaders.get(zip);
     53                 if (loader != null) {
     54                     return loader;
     55                 }
     56 
     57                 PathClassLoader pathClassloader =
     58                     new PathClassLoader(zip, libPath, parent);
     59 
     60                 mLoaders.put(zip, pathClassloader);
     61                 return pathClassloader;
     62             }
     63 
     64             return new PathClassLoader(zip, parent);
     65         }
     66     }
     67 
     68     private final Map<String, ClassLoader> mLoaders = new HashMap<String, ClassLoader>();
     69 
     70     private static final ApplicationLoaders gApplicationLoaders
     71         = new ApplicationLoaders();
     72 }
     73