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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 android.os.Trace;
     20 import android.util.ArrayMap;
     21 import dalvik.system.PathClassLoader;
     22 
     23 class ApplicationLoaders
     24 {
     25     public static ApplicationLoaders getDefault()
     26     {
     27         return gApplicationLoaders;
     28     }
     29 
     30     public ClassLoader getClassLoader(String zip, String libPath, ClassLoader parent)
     31     {
     32         /*
     33          * This is the parent we use if they pass "null" in.  In theory
     34          * this should be the "system" class loader; in practice we
     35          * don't use that and can happily (and more efficiently) use the
     36          * bootstrap class loader.
     37          */
     38         ClassLoader baseParent = ClassLoader.getSystemClassLoader().getParent();
     39 
     40         synchronized (mLoaders) {
     41             if (parent == null) {
     42                 parent = baseParent;
     43             }
     44 
     45             /*
     46              * If we're one step up from the base class loader, find
     47              * something in our cache.  Otherwise, we create a whole
     48              * new ClassLoader for the zip archive.
     49              */
     50             if (parent == baseParent) {
     51                 ClassLoader loader = mLoaders.get(zip);
     52                 if (loader != null) {
     53                     return loader;
     54                 }
     55 
     56                 Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, zip);
     57                 PathClassLoader pathClassloader =
     58                     new PathClassLoader(zip, libPath, parent);
     59                 Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     60 
     61                 mLoaders.put(zip, pathClassloader);
     62                 return pathClassloader;
     63             }
     64 
     65             Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, zip);
     66             PathClassLoader pathClassloader = new PathClassLoader(zip, parent);
     67             Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     68             return pathClassloader;
     69         }
     70     }
     71 
     72     private final ArrayMap<String, ClassLoader> mLoaders = new ArrayMap<String, ClassLoader>();
     73 
     74     private static final ApplicationLoaders gApplicationLoaders
     75         = new ApplicationLoaders();
     76 }
     77