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 public final class LoaderPool {
  41 
  42     /** Maps module names to class loaders. */
  43     private final Map<String, Loader> loaders;
  44 
  45 
  46     /**
  47      * Creates a pool of class loaders. Each module in the given configuration
  48      * will be loaded its own class loader in the pool. The class loader is
  49      * created with the given parent class loader as its parent.
  50      */
  51     public LoaderPool(Configuration cf,
  52                       List<ModuleLayer> parentLayers,
  53                       ClassLoader parentLoader)
  54     {
  55         Map<String, Loader> loaders = new HashMap<>();
  56         for (ResolvedModule resolvedModule : cf.modules()) {
  57             Loader loader = new Loader(resolvedModule, this, parentLoader);
  58             String mn = resolvedModule.name();
  59             loaders.put(mn, loader);
  60         }
  61         this.loaders = loaders;
  62 
  63         // complete the initialization
  64         loaders.values().forEach(l -> l.initRemotePackageMap(cf, parentLayers));
  65     }
  66 
  67 
  68     /**
  69      * Returns the class loader for the named module
  70      */
  71     public Loader loaderFor(String name) {
  72         Loader loader = loaders.get(name);
  73         assert loader != null;
  74         return loader;
  75     }
  76 
  77     /**
  78      * Returns a stream of the loaders in this pool.
  79      */
  80     public Stream<Loader> loaders() {
  81         return loaders.values().stream();
  82     }
  83 
  84 }