1 /*
   2  * Copyright (c) 2015, 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 
  26 package jdk.internal.loader;
  27 
  28 import java.lang.module.Configuration;
  29 import java.lang.module.ResolvedModule;
  30 import java.util.HashMap;
  31 import java.util.List;
  32 import java.util.Map;
  33 import java.util.stream.Stream;
  34 
  35 /**
  36  * A pool of class loaders.
  37  *
  38  * @see ModuleLayer#defineModulesWithManyLoaders
  39  */
  40 
  41 public final class LoaderPool {
  42 
  43     // maps module names to class loaders
  44     private final Map<String, Loader> loaders;
  45 
  46 
  47     /**
  48      * Creates a pool of class loaders. Each module in the given configuration
  49      * will be loaded its own class loader in the pool. The class loader is
  50      * created with the given parent class loader as its parent.
  51      */
  52     public LoaderPool(Configuration cf,
  53                       List<ModuleLayer> parentLayers,
  54                       ClassLoader parentLoader)
  55     {
  56         Map<String, Loader> loaders = new HashMap<>();
  57         for (ResolvedModule resolvedModule : cf.modules()) {
  58             Loader loader = new Loader(resolvedModule, this, parentLoader);
  59             String mn = resolvedModule.name();
  60             loaders.put(mn, loader);
  61         }
  62         this.loaders = loaders;
  63 
  64         // complete the initialization
  65         loaders.values().forEach(l -> l.initRemotePackageMap(cf, parentLayers));
  66     }
  67 
  68 
  69     /**
  70      * Returns the class loader for the named module
  71      */
  72     public Loader loaderFor(String name) {
  73         Loader loader = loaders.get(name);
  74         assert loader != null;
  75         return loader;
  76     }
  77 
  78     /**
  79      * Returns a stream of the loaders in this pool.
  80      */
  81     public Stream<Loader> loaders() {
  82         return loaders.values().stream();
  83     }
  84 
  85 }
  86