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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 dalvik.system.PathClassLoader;
     21 
     22 import java.util.HashMap;
     23 import java.util.Map;
     24 
     25 class ApplicationLoaders
     26 {
     27     public static ApplicationLoaders getDefault()
     28     {
     29         return gApplicationLoaders;
     30     }
     31 
     32     public ClassLoader getClassLoader(String zip, String libPath, ClassLoader parent)
     33     {
     34         /*
     35          * This is the parent we use if they pass "null" in.  In theory
     36          * this should be the "system" class loader; in practice we
     37          * don't use that and can happily (and more efficiently) use the
     38          * bootstrap class loader.
     39          */
     40         ClassLoader baseParent = ClassLoader.getSystemClassLoader().getParent();
     41 
     42         synchronized (mLoaders) {
     43             if (parent == null) {
     44                 parent = baseParent;
     45             }
     46 
     47             /*
     48              * If we're one step up from the base class loader, find
     49              * something in our cache.  Otherwise, we create a whole
     50              * new ClassLoader for the zip archive.
     51              */
     52             if (parent == baseParent) {
     53                 ClassLoader loader = mLoaders.get(zip);
     54                 if (loader != null) {
     55                     return loader;
     56                 }
     57 
     58                 Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, zip);
     59                 PathClassLoader pathClassloader =
     60                     new PathClassLoader(zip, libPath, parent);
     61                 Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     62 
     63                 mLoaders.put(zip, pathClassloader);
     64                 return pathClassloader;
     65             }
     66 
     67             Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, zip);
     68             PathClassLoader pathClassloader = new PathClassLoader(zip, parent);
     69             Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     70             return pathClassloader;
     71         }
     72     }
     73 
     74     private final Map<String, ClassLoader> mLoaders = new HashMap<String, ClassLoader>();
     75 
     76     private static final ApplicationLoaders gApplicationLoaders
     77         = new ApplicationLoaders();
     78 }
     79