author | erikj |
Tue, 12 Sep 2017 19:03:39 +0200 | |
changeset 47216 | 71c04702a3d5 |
parent 47004 | jdk/src/java.base/share/classes/java/lang/ModuleLayer.java@b7e72fc752c9 |
child 47866 | 39db80b32b69 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package java.lang; |
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import java.lang.module.Configuration; |
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import java.lang.module.ModuleDescriptor; |
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import java.lang.module.ResolvedModule; |
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import java.util.ArrayDeque; |
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import java.util.ArrayList; |
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import java.util.Collections; |
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import java.util.Deque; |
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import java.util.HashMap; |
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import java.util.HashSet; |
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import java.util.List; |
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import java.util.Map; |
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import java.util.Objects; |
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import java.util.Optional; |
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import java.util.Set; |
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import java.util.concurrent.CopyOnWriteArrayList; |
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import java.util.function.Function; |
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import java.util.stream.Collectors; |
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import java.util.stream.Stream; |
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import jdk.internal.loader.ClassLoaderValue; |
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import jdk.internal.loader.Loader; |
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import jdk.internal.loader.LoaderPool; |
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import jdk.internal.module.ServicesCatalog; |
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import sun.security.util.SecurityConstants; |
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/** |
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* A layer of modules in the Java virtual machine. |
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* |
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* <p> A layer is created from a graph of modules in a {@link Configuration} |
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* and a function that maps each module to a {@link ClassLoader}. |
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* Creating a layer informs the Java virtual machine about the classes that |
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* may be loaded from the modules so that the Java virtual machine knows which |
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* module that each class is a member of. </p> |
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* |
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* <p> Creating a layer creates a {@link Module} object for each {@link |
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* ResolvedModule} in the configuration. For each resolved module that is |
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* {@link ResolvedModule#reads() read}, the {@code Module} {@link |
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* Module#canRead reads} the corresponding run-time {@code Module}, which may |
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* be in the same layer or a {@link #parents() parent} layer. </p> |
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* |
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* <p> The {@link #defineModulesWithOneLoader defineModulesWithOneLoader} and |
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* {@link #defineModulesWithManyLoaders defineModulesWithManyLoaders} methods |
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* provide convenient ways to create a module layer where all modules are |
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* mapped to a single class loader or where each module is mapped to its own |
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* class loader. The {@link #defineModules defineModules} method is for more |
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* advanced cases where modules are mapped to custom class loaders by means of |
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* a function specified to the method. Each of these methods has an instance |
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* and static variant. The instance methods create a layer with the receiver |
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* as the parent layer. The static methods are for more advanced cases where |
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* there can be more than one parent layer or where a {@link |
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* ModuleLayer.Controller Controller} is needed to control modules in the layer |
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* </p> |
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* |
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* <p> A Java virtual machine has at least one non-empty layer, the {@link |
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* #boot() boot} layer, that is created when the Java virtual machine is |
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* started. The boot layer contains module {@code java.base} and is the only |
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* layer in the Java virtual machine with a module named "{@code java.base}". |
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* The modules in the boot layer are mapped to the bootstrap class loader and |
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* other class loaders that are <a href="ClassLoader.html#builtinLoaders"> |
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* built-in</a> into the Java virtual machine. The boot layer will often be |
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* the {@link #parents() parent} when creating additional layers. </p> |
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* |
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* <p> Each {@code Module} in a layer is created so that it {@link |
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* Module#isExported(String) exports} and {@link Module#isOpen(String) opens} |
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* the packages described by its {@link ModuleDescriptor}. Qualified exports |
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* (where a package is exported to a set of target modules rather than all |
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* modules) are reified when creating the layer as follows: </p> |
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* <ul> |
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* <li> If module {@code X} exports a package to {@code Y}, and if the |
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* runtime {@code Module} {@code X} reads {@code Module} {@code Y}, then |
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* the package is exported to {@code Module} {@code Y} (which may be in |
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* the same layer as {@code X} or a parent layer). </li> |
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* |
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* <li> If module {@code X} exports a package to {@code Y}, and if the |
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* runtime {@code Module} {@code X} does not read {@code Y} then target |
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* {@code Y} is located as if by invoking {@link #findModule(String) |
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* findModule} to find the module in the layer or its parent layers. If |
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* {@code Y} is found then the package is exported to the instance of |
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* {@code Y} that was found. If {@code Y} is not found then the qualified |
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* export is ignored. </li> |
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* </ul> |
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* |
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* <p> Qualified opens are handled in same way as qualified exports. </p> |
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* |
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* <p> As when creating a {@code Configuration}, |
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* {@link ModuleDescriptor#isAutomatic() automatic} modules receive special |
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* treatment when creating a layer. An automatic module is created in the |
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* Java virtual machine as a {@code Module} that reads every unnamed {@code |
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* Module} in the Java virtual machine. </p> |
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* |
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* <p> Unless otherwise specified, passing a {@code null} argument to a method |
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* in this class causes a {@link NullPointerException NullPointerException} to |
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* be thrown. </p> |
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* |
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* <h3> Example usage: </h3> |
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* |
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* <p> This example creates a configuration by resolving a module named |
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* "{@code myapp}" with the configuration for the boot layer as the parent. It |
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* then creates a new layer with the modules in this configuration. All modules |
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* are defined to the same class loader. </p> |
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* |
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* <pre>{@code |
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* ModuleFinder finder = ModuleFinder.of(dir1, dir2, dir3); |
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* |
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* ModuleLayer parent = ModuleLayer.boot(); |
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* |
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* Configuration cf = parent.configuration().resolve(finder, ModuleFinder.of(), Set.of("myapp")); |
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* |
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* ClassLoader scl = ClassLoader.getSystemClassLoader(); |
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* |
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* ModuleLayer layer = parent.defineModulesWithOneLoader(cf, scl); |
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* |
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* Class<?> c = layer.findLoader("myapp").loadClass("app.Main"); |
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* }</pre> |
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* |
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* @since 9 |
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* @spec JPMS |
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* @see Module#getLayer() |
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*/ |
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public final class ModuleLayer { |
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// the empty layer |
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private static final ModuleLayer EMPTY_LAYER |
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= new ModuleLayer(Configuration.empty(), List.of(), null); |
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// the configuration from which this ;ayer was created |
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private final Configuration cf; |
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// parent layers, empty in the case of the empty layer |
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private final List<ModuleLayer> parents; |
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// maps module name to jlr.Module |
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private final Map<String, Module> nameToModule; |
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/** |
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* Creates a new module layer from the modules in the given configuration. |
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*/ |
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private ModuleLayer(Configuration cf, |
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List<ModuleLayer> parents, |
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Function<String, ClassLoader> clf) |
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{ |
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this.cf = cf; |
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this.parents = parents; // no need to do defensive copy |
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Map<String, Module> map; |
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if (parents.isEmpty()) { |
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map = Collections.emptyMap(); |
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} else { |
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map = Module.defineModules(cf, clf, this); |
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} |
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this.nameToModule = map; // no need to do defensive copy |
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} |
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/** |
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* Controls a module layer. The static methods defined by {@link ModuleLayer} |
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* to create module layers return a {@code Controller} that can be used to |
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* control modules in the layer. |
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* |
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* <p> Unless otherwise specified, passing a {@code null} argument to a |
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* method in this class causes a {@link NullPointerException |
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* NullPointerException} to be thrown. </p> |
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* |
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* @apiNote Care should be taken with {@code Controller} objects, they |
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* should never be shared with untrusted code. |
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* |
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* @since 9 |
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* @spec JPMS |
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*/ |
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public static final class Controller { |
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private final ModuleLayer layer; |
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Controller(ModuleLayer layer) { |
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this.layer = layer; |
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} |
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/** |
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* Returns the layer that this object controls. |
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* |
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* @return the module layer |
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*/ |
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public ModuleLayer layer() { |
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return layer; |
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} |
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private void ensureInLayer(Module source) { |
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if (source.getLayer() != layer) |
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throw new IllegalArgumentException(source + " not in layer"); |
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} |
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/** |
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* Updates module {@code source} in the layer to read module |
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* {@code target}. This method is a no-op if {@code source} already |
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* reads {@code target}. |
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* |
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* @implNote <em>Read edges</em> added by this method are <em>weak</em> |
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* and do not prevent {@code target} from being GC'ed when {@code source} |
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* is strongly reachable. |
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* |
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* @param source |
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* The source module |
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* @param target |
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* The target module to read |
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* |
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* @return This controller |
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* |
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* @throws IllegalArgumentException |
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* If {@code source} is not in the module layer |
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* |
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* @see Module#addReads |
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*/ |
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public Controller addReads(Module source, Module target) { |
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ensureInLayer(source); |
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source.implAddReads(target); |
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return this; |
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} |
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/** |
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* Updates module {@code source} in the layer to export a package to |
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* module {@code target}. This method is a no-op if {@code source} |
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* already exports the package to at least {@code target}. |
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* |
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* @param source |
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* The source module |
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* @param pn |
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* The package name |
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* @param target |
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* The target module |
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* |
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* @return This controller |
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* |
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* @throws IllegalArgumentException |
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* If {@code source} is not in the module layer or the package |
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* is not in the source module |
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* |
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* @see Module#addExports |
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*/ |
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public Controller addExports(Module source, String pn, Module target) { |
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ensureInLayer(source); |
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source.implAddExports(pn, target); |
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return this; |
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} |
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/** |
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* Updates module {@code source} in the layer to open a package to |
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* module {@code target}. This method is a no-op if {@code source} |
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* already opens the package to at least {@code target}. |
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* |
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* @param source |
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* The source module |
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* @param pn |
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* The package name |
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* @param target |
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* The target module |
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* |
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* @return This controller |
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* |
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* @throws IllegalArgumentException |
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* If {@code source} is not in the module layer or the package |
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* is not in the source module |
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* |
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* @see Module#addOpens |
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*/ |
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public Controller addOpens(Module source, String pn, Module target) { |
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ensureInLayer(source); |
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source.implAddOpens(pn, target); |
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return this; |
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} |
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} |
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/** |
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* Creates a new module layer, with this layer as its parent, by defining the |
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* modules in the given {@code Configuration} to the Java virtual machine. |
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* This method creates one class loader and defines all modules to that |
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* class loader. The {@link ClassLoader#getParent() parent} of each class |
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* loader is the given parent class loader. This method works exactly as |
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* specified by the static {@link |
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* #defineModulesWithOneLoader(Configuration,List,ClassLoader) |
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* defineModulesWithOneLoader} method when invoked with this layer as the |
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* parent. In other words, if this layer is {@code thisLayer} then this |
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* method is equivalent to invoking: |
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* <pre> {@code |
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* ModuleLayer.defineModulesWithOneLoader(cf, List.of(thisLayer), parentLoader).layer(); |
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* }</pre> |
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* |
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* @param cf |
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* The configuration for the layer |
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* @param parentLoader |
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* The parent class loader for the class loader created by this |
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* method; may be {@code null} for the bootstrap class loader |
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* |
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* @return The newly created layer |
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* |
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* @throws IllegalArgumentException |
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* If the parent of the given configuration is not the configuration |
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* for this layer |
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* @throws LayerInstantiationException |
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* If the layer cannot be created for any of the reasons specified |
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* by the static {@code defineModulesWithOneLoader} method |
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* @throws SecurityException |
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* If {@code RuntimePermission("createClassLoader")} or |
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* {@code RuntimePermission("getClassLoader")} is denied by |
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* the security manager |
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* |
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* @see #findLoader |
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*/ |
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public ModuleLayer defineModulesWithOneLoader(Configuration cf, |
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ClassLoader parentLoader) { |
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return defineModulesWithOneLoader(cf, List.of(this), parentLoader).layer(); |
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} |
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/** |
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* Creates a new module layer, with this layer as its parent, by defining the |
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* modules in the given {@code Configuration} to the Java virtual machine. |
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* Each module is defined to its own {@link ClassLoader} created by this |
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* method. The {@link ClassLoader#getParent() parent} of each class loader |
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* is the given parent class loader. This method works exactly as specified |
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* by the static {@link |
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* #defineModulesWithManyLoaders(Configuration,List,ClassLoader) |
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* defineModulesWithManyLoaders} method when invoked with this layer as the |
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* parent. In other words, if this layer is {@code thisLayer} then this |
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* method is equivalent to invoking: |
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* <pre> {@code |
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* ModuleLayer.defineModulesWithManyLoaders(cf, List.of(thisLayer), parentLoader).layer(); |
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* }</pre> |
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* |
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* @param cf |
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* The configuration for the layer |
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* @param parentLoader |
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* The parent class loader for each of the class loaders created by |
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* this method; may be {@code null} for the bootstrap class loader |
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* |
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* @return The newly created layer |
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* |
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* @throws IllegalArgumentException |
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* If the parent of the given configuration is not the configuration |
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* for this layer |
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* @throws LayerInstantiationException |
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* If the layer cannot be created for any of the reasons specified |
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* by the static {@code defineModulesWithManyLoaders} method |
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* @throws SecurityException |
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* If {@code RuntimePermission("createClassLoader")} or |
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* {@code RuntimePermission("getClassLoader")} is denied by |
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* the security manager |
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* |
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* @see #findLoader |
|
378 |
*/ |
|
379 |
public ModuleLayer defineModulesWithManyLoaders(Configuration cf, |
|
380 |
ClassLoader parentLoader) { |
|
381 |
return defineModulesWithManyLoaders(cf, List.of(this), parentLoader).layer(); |
|
382 |
} |
|
383 |
||
384 |
||
385 |
/** |
|
386 |
* Creates a new module layer, with this layer as its parent, by defining the |
|
387 |
* modules in the given {@code Configuration} to the Java virtual machine. |
|
388 |
* Each module is mapped, by name, to its class loader by means of the |
|
389 |
* given function. This method works exactly as specified by the static |
|
390 |
* {@link #defineModules(Configuration,List,Function) defineModules} |
|
391 |
* method when invoked with this layer as the parent. In other words, if |
|
392 |
* this layer is {@code thisLayer} then this method is equivalent to |
|
393 |
* invoking: |
|
394 |
* <pre> {@code |
|
395 |
* ModuleLayer.defineModules(cf, List.of(thisLayer), clf).layer(); |
|
396 |
* }</pre> |
|
397 |
* |
|
398 |
* @param cf |
|
399 |
* The configuration for the layer |
|
400 |
* @param clf |
|
401 |
* The function to map a module name to a class loader |
|
402 |
* |
|
403 |
* @return The newly created layer |
|
404 |
* |
|
405 |
* @throws IllegalArgumentException |
|
406 |
* If the parent of the given configuration is not the configuration |
|
407 |
* for this layer |
|
408 |
* @throws LayerInstantiationException |
|
409 |
* If the layer cannot be created for any of the reasons specified |
|
410 |
* by the static {@code defineModules} method |
|
411 |
* @throws SecurityException |
|
412 |
* If {@code RuntimePermission("getClassLoader")} is denied by |
|
413 |
* the security manager |
|
414 |
*/ |
|
415 |
public ModuleLayer defineModules(Configuration cf, |
|
416 |
Function<String, ClassLoader> clf) { |
|
417 |
return defineModules(cf, List.of(this), clf).layer(); |
|
418 |
} |
|
419 |
||
420 |
/** |
|
421 |
* Creates a new module layer by defining the modules in the given {@code |
|
422 |
* Configuration} to the Java virtual machine. This method creates one |
|
423 |
* class loader and defines all modules to that class loader. |
|
424 |
* |
|
425 |
* <p> The class loader created by this method implements <em>direct |
|
45652
33342314ce89
8181087: Module system implementation refresh (6/2017)
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diff
changeset
|
426 |
* delegation</em> when loading classes from modules. If the {@link |
44545 | 427 |
* ClassLoader#loadClass(String, boolean) loadClass} method is invoked to |
428 |
* load a class then it uses the package name of the class to map it to a |
|
429 |
* module. This may be a module in this layer and hence defined to the same |
|
430 |
* class loader. It may be a package in a module in a parent layer that is |
|
431 |
* exported to one or more of the modules in this layer. The class |
|
432 |
* loader delegates to the class loader of the module, throwing {@code |
|
433 |
* ClassNotFoundException} if not found by that class loader. |
|
434 |
* When {@code loadClass} is invoked to load classes that do not map to a |
|
435 |
* module then it delegates to the parent class loader. </p> |
|
436 |
* |
|
45652
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diff
changeset
|
437 |
* <p> The class loader created by this method locates resources |
33342314ce89
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diff
changeset
|
438 |
* ({@link ClassLoader#getResource(String) getResource}, {@link |
33342314ce89
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diff
changeset
|
439 |
* ClassLoader#getResources(String) getResources}, and other resource |
33342314ce89
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diff
changeset
|
440 |
* methods) in all modules in the layer before searching the parent class |
33342314ce89
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diff
changeset
|
441 |
* loader. </p> |
33342314ce89
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parents:
45138
diff
changeset
|
442 |
* |
44545 | 443 |
* <p> Attempting to create a layer with all modules defined to the same |
444 |
* class loader can fail for the following reasons: |
|
445 |
* |
|
446 |
* <ul> |
|
447 |
* |
|
448 |
* <li><p> <em>Overlapping packages</em>: Two or more modules in the |
|
449 |
* configuration have the same package. </p></li> |
|
450 |
* |
|
451 |
* <li><p> <em>Split delegation</em>: The resulting class loader would |
|
45652
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diff
changeset
|
452 |
* need to delegate to more than one class loader in order to load |
33342314ce89
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45138
diff
changeset
|
453 |
* classes in a specific package. </p></li> |
44545 | 454 |
* |
455 |
* </ul> |
|
456 |
* |
|
457 |
* <p> In addition, a layer cannot be created if the configuration contains |
|
458 |
* a module named "{@code java.base}", or a module contains a package named |
|
459 |
* "{@code java}" or a package with a name starting with "{@code java.}". </p> |
|
460 |
* |
|
461 |
* <p> If there is a security manager then the class loader created by |
|
462 |
* this method will load classes and resources with privileges that are |
|
463 |
* restricted by the calling context of this method. </p> |
|
464 |
* |
|
465 |
* @param cf |
|
466 |
* The configuration for the layer |
|
467 |
* @param parentLayers |
|
468 |
* The list of parent layers in search order |
|
469 |
* @param parentLoader |
|
470 |
* The parent class loader for the class loader created by this |
|
471 |
* method; may be {@code null} for the bootstrap class loader |
|
472 |
* |
|
473 |
* @return A controller that controls the newly created layer |
|
474 |
* |
|
475 |
* @throws IllegalArgumentException |
|
476 |
* If the parent configurations do not match the configuration of |
|
477 |
* the parent layers, including order |
|
478 |
* @throws LayerInstantiationException |
|
479 |
* If all modules cannot be defined to the same class loader for any |
|
480 |
* of the reasons listed above |
|
481 |
* @throws SecurityException |
|
482 |
* If {@code RuntimePermission("createClassLoader")} or |
|
483 |
* {@code RuntimePermission("getClassLoader")} is denied by |
|
484 |
* the security manager |
|
485 |
* |
|
486 |
* @see #findLoader |
|
487 |
*/ |
|
488 |
public static Controller defineModulesWithOneLoader(Configuration cf, |
|
489 |
List<ModuleLayer> parentLayers, |
|
490 |
ClassLoader parentLoader) |
|
491 |
{ |
|
492 |
List<ModuleLayer> parents = new ArrayList<>(parentLayers); |
|
493 |
checkConfiguration(cf, parents); |
|
494 |
||
495 |
checkCreateClassLoaderPermission(); |
|
496 |
checkGetClassLoaderPermission(); |
|
497 |
||
498 |
try { |
|
499 |
Loader loader = new Loader(cf.modules(), parentLoader); |
|
500 |
loader.initRemotePackageMap(cf, parents); |
|
501 |
ModuleLayer layer = new ModuleLayer(cf, parents, mn -> loader); |
|
502 |
return new Controller(layer); |
|
503 |
} catch (IllegalArgumentException | IllegalStateException e) { |
|
504 |
throw new LayerInstantiationException(e.getMessage()); |
|
505 |
} |
|
506 |
} |
|
507 |
||
508 |
/** |
|
509 |
* Creates a new module layer by defining the modules in the given {@code |
|
510 |
* Configuration} to the Java virtual machine. Each module is defined to |
|
511 |
* its own {@link ClassLoader} created by this method. The {@link |
|
512 |
* ClassLoader#getParent() parent} of each class loader is the given parent |
|
513 |
* class loader. |
|
514 |
* |
|
515 |
* <p> The class loaders created by this method implement <em>direct |
|
45652
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
516 |
* delegation</em> when loading classes from modules. If the {@link |
44545 | 517 |
* ClassLoader#loadClass(String, boolean) loadClass} method is invoked to |
518 |
* load a class then it uses the package name of the class to map it to a |
|
519 |
* module. The package may be in the module defined to the class loader. |
|
520 |
* The package may be exported by another module in this layer to the |
|
521 |
* module defined to the class loader. It may be in a package exported by a |
|
522 |
* module in a parent layer. The class loader delegates to the class loader |
|
523 |
* of the module, throwing {@code ClassNotFoundException} if not found by |
|
45652
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
524 |
* that class loader. When {@code loadClass} is invoked to load a class |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
525 |
* that does not map to a module then it delegates to the parent class |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
526 |
* loader. </p> |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
527 |
* |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
528 |
* <p> The class loaders created by this method locate resources |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
529 |
* ({@link ClassLoader#getResource(String) getResource}, {@link |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
530 |
* ClassLoader#getResources(String) getResources}, and other resource |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
531 |
* methods) in the module defined to the class loader before searching |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
532 |
* the parent class loader. </p> |
44545 | 533 |
* |
534 |
* <p> If there is a security manager then the class loaders created by |
|
535 |
* this method will load classes and resources with privileges that are |
|
536 |
* restricted by the calling context of this method. </p> |
|
537 |
* |
|
538 |
* @param cf |
|
539 |
* The configuration for the layer |
|
540 |
* @param parentLayers |
|
541 |
* The list of parent layers in search order |
|
542 |
* @param parentLoader |
|
543 |
* The parent class loader for each of the class loaders created by |
|
544 |
* this method; may be {@code null} for the bootstrap class loader |
|
545 |
* |
|
546 |
* @return A controller that controls the newly created layer |
|
547 |
* |
|
548 |
* @throws IllegalArgumentException |
|
549 |
* If the parent configurations do not match the configuration of |
|
550 |
* the parent layers, including order |
|
551 |
* @throws LayerInstantiationException |
|
552 |
* If the layer cannot be created because the configuration contains |
|
553 |
* a module named "{@code java.base}" or a module contains a package |
|
554 |
* named "{@code java}" or a package with a name starting with |
|
555 |
* "{@code java.}" |
|
556 |
* |
|
557 |
* @throws SecurityException |
|
558 |
* If {@code RuntimePermission("createClassLoader")} or |
|
559 |
* {@code RuntimePermission("getClassLoader")} is denied by |
|
560 |
* the security manager |
|
561 |
* |
|
562 |
* @see #findLoader |
|
563 |
*/ |
|
564 |
public static Controller defineModulesWithManyLoaders(Configuration cf, |
|
565 |
List<ModuleLayer> parentLayers, |
|
566 |
ClassLoader parentLoader) |
|
567 |
{ |
|
568 |
List<ModuleLayer> parents = new ArrayList<>(parentLayers); |
|
569 |
checkConfiguration(cf, parents); |
|
570 |
||
571 |
checkCreateClassLoaderPermission(); |
|
572 |
checkGetClassLoaderPermission(); |
|
573 |
||
574 |
LoaderPool pool = new LoaderPool(cf, parents, parentLoader); |
|
575 |
try { |
|
576 |
ModuleLayer layer = new ModuleLayer(cf, parents, pool::loaderFor); |
|
577 |
return new Controller(layer); |
|
578 |
} catch (IllegalArgumentException | IllegalStateException e) { |
|
579 |
throw new LayerInstantiationException(e.getMessage()); |
|
580 |
} |
|
581 |
} |
|
582 |
||
583 |
/** |
|
584 |
* Creates a new module layer by defining the modules in the given {@code |
|
585 |
* Configuration} to the Java virtual machine. The given function maps each |
|
586 |
* module in the configuration, by name, to a class loader. Creating the |
|
587 |
* layer informs the Java virtual machine about the classes that may be |
|
588 |
* loaded so that the Java virtual machine knows which module that each |
|
589 |
* class is a member of. |
|
590 |
* |
|
591 |
* <p> The class loader delegation implemented by the class loaders must |
|
592 |
* respect module readability. The class loaders should be |
|
593 |
* {@link ClassLoader#registerAsParallelCapable parallel-capable} so as to |
|
594 |
* avoid deadlocks during class loading. In addition, the entity creating |
|
595 |
* a new layer with this method should arrange that the class loaders be |
|
596 |
* ready to load from these modules before there are any attempts to load |
|
597 |
* classes or resources. </p> |
|
598 |
* |
|
599 |
* <p> Creating a layer can fail for the following reasons: </p> |
|
600 |
* |
|
601 |
* <ul> |
|
602 |
* |
|
603 |
* <li><p> Two or more modules with the same package are mapped to the |
|
604 |
* same class loader. </p></li> |
|
605 |
* |
|
606 |
* <li><p> A module is mapped to a class loader that already has a |
|
607 |
* module of the same name defined to it. </p></li> |
|
608 |
* |
|
609 |
* <li><p> A module is mapped to a class loader that has already |
|
610 |
* defined types in any of the packages in the module. </p></li> |
|
611 |
* |
|
612 |
* </ul> |
|
613 |
* |
|
614 |
* <p> In addition, a layer cannot be created if the configuration contains |
|
615 |
* a module named "{@code java.base}", a configuration contains a module |
|
616 |
* with a package named "{@code java}" or a package name starting with |
|
45652
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
617 |
* "{@code java.}", or the function to map a module name to a class loader |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
618 |
* returns {@code null} or the {@linkplain ClassLoader#getPlatformClassLoader() |
33342314ce89
8181087: Module system implementation refresh (6/2017)
alanb
parents:
45138
diff
changeset
|
619 |
* platform class loader}. </p> |
44545 | 620 |
* |
621 |
* <p> If the function to map a module name to class loader throws an error |
|
622 |
* or runtime exception then it is propagated to the caller of this method. |
|
623 |
* </p> |
|
624 |
* |
|
625 |
* @apiNote It is implementation specific as to whether creating a layer |
|
626 |
* with this method is an atomic operation or not. Consequentially it is |
|
627 |
* possible for this method to fail with some modules, but not all, defined |
|
628 |
* to the Java virtual machine. |
|
629 |
* |
|
630 |
* @param cf |
|
631 |
* The configuration for the layer |
|
632 |
* @param parentLayers |
|
633 |
* The list of parent layers in search order |
|
634 |
* @param clf |
|
635 |
* The function to map a module name to a class loader |
|
636 |
* |
|
637 |
* @return A controller that controls the newly created layer |
|
638 |
* |
|
639 |
* @throws IllegalArgumentException |
|
640 |
* If the parent configurations do not match the configuration of |
|
641 |
* the parent layers, including order |
|
642 |
* @throws LayerInstantiationException |
|
643 |
* If creating the layer fails for any of the reasons listed above |
|
644 |
* @throws SecurityException |
|
645 |
* If {@code RuntimePermission("getClassLoader")} is denied by |
|
646 |
* the security manager |
|
647 |
*/ |
|
648 |
public static Controller defineModules(Configuration cf, |
|
649 |
List<ModuleLayer> parentLayers, |
|
650 |
Function<String, ClassLoader> clf) |
|
651 |
{ |
|
652 |
List<ModuleLayer> parents = new ArrayList<>(parentLayers); |
|
653 |
checkConfiguration(cf, parents); |
|
654 |
Objects.requireNonNull(clf); |
|
655 |
||
656 |
checkGetClassLoaderPermission(); |
|
657 |
||
658 |
// The boot layer is checked during module system initialization |
|
659 |
if (boot() != null) { |
|
660 |
checkForDuplicatePkgs(cf, clf); |
|
661 |
} |
|
662 |
||
663 |
try { |
|
664 |
ModuleLayer layer = new ModuleLayer(cf, parents, clf); |
|
665 |
return new Controller(layer); |
|
666 |
} catch (IllegalArgumentException | IllegalStateException e) { |
|
667 |
throw new LayerInstantiationException(e.getMessage()); |
|
668 |
} |
|
669 |
} |
|
670 |
||
671 |
||
672 |
/** |
|
673 |
* Checks that the parent configurations match the configuration of |
|
674 |
* the parent layers. |
|
675 |
*/ |
|
676 |
private static void checkConfiguration(Configuration cf, |
|
677 |
List<ModuleLayer> parentLayers) |
|
678 |
{ |
|
679 |
Objects.requireNonNull(cf); |
|
680 |
||
681 |
List<Configuration> parentConfigurations = cf.parents(); |
|
682 |
if (parentLayers.size() != parentConfigurations.size()) |
|
683 |
throw new IllegalArgumentException("wrong number of parents"); |
|
684 |
||
685 |
int index = 0; |
|
686 |
for (ModuleLayer parent : parentLayers) { |
|
687 |
if (parent.configuration() != parentConfigurations.get(index)) { |
|
688 |
throw new IllegalArgumentException( |
|
689 |
"Parent of configuration != configuration of this Layer"); |
|
690 |
} |
|
691 |
index++; |
|
692 |
} |
|
693 |
} |
|
694 |
||
695 |
private static void checkCreateClassLoaderPermission() { |
|
696 |
SecurityManager sm = System.getSecurityManager(); |
|
697 |
if (sm != null) |
|
698 |
sm.checkPermission(SecurityConstants.CREATE_CLASSLOADER_PERMISSION); |
|
699 |
} |
|
700 |
||
701 |
private static void checkGetClassLoaderPermission() { |
|
702 |
SecurityManager sm = System.getSecurityManager(); |
|
703 |
if (sm != null) |
|
704 |
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); |
|
705 |
} |
|
706 |
||
707 |
/** |
|
708 |
* Checks a configuration and the module-to-loader mapping to ensure that |
|
709 |
* no two modules mapped to the same class loader have the same package. |
|
710 |
* It also checks that no two automatic modules have the same package. |
|
711 |
* |
|
712 |
* @throws LayerInstantiationException |
|
713 |
*/ |
|
714 |
private static void checkForDuplicatePkgs(Configuration cf, |
|
715 |
Function<String, ClassLoader> clf) |
|
716 |
{ |
|
717 |
// HashMap allows null keys |
|
718 |
Map<ClassLoader, Set<String>> loaderToPackages = new HashMap<>(); |
|
719 |
for (ResolvedModule resolvedModule : cf.modules()) { |
|
720 |
ModuleDescriptor descriptor = resolvedModule.reference().descriptor(); |
|
721 |
ClassLoader loader = clf.apply(descriptor.name()); |
|
722 |
||
723 |
Set<String> loaderPackages |
|
724 |
= loaderToPackages.computeIfAbsent(loader, k -> new HashSet<>()); |
|
725 |
||
726 |
for (String pkg : descriptor.packages()) { |
|
727 |
boolean added = loaderPackages.add(pkg); |
|
728 |
if (!added) { |
|
729 |
throw fail("More than one module with package %s mapped" + |
|
730 |
" to the same class loader", pkg); |
|
731 |
} |
|
732 |
} |
|
733 |
} |
|
734 |
} |
|
735 |
||
736 |
/** |
|
737 |
* Creates a LayerInstantiationException with the a message formatted from |
|
738 |
* the given format string and arguments. |
|
739 |
*/ |
|
740 |
private static LayerInstantiationException fail(String fmt, Object ... args) { |
|
741 |
String msg = String.format(fmt, args); |
|
742 |
return new LayerInstantiationException(msg); |
|
743 |
} |
|
744 |
||
745 |
||
746 |
/** |
|
747 |
* Returns the configuration for this layer. |
|
748 |
* |
|
749 |
* @return The configuration for this layer |
|
750 |
*/ |
|
751 |
public Configuration configuration() { |
|
752 |
return cf; |
|
753 |
} |
|
754 |
||
755 |
||
756 |
/** |
|
757 |
* Returns the list of this layer's parents unless this is the |
|
758 |
* {@linkplain #empty empty layer}, which has no parents and so an |
|
759 |
* empty list is returned. |
|
760 |
* |
|
761 |
* @return The list of this layer's parents |
|
762 |
*/ |
|
763 |
public List<ModuleLayer> parents() { |
|
764 |
return parents; |
|
765 |
} |
|
766 |
||
767 |
||
768 |
/** |
|
769 |
* Returns an ordered stream of layers. The first element is is this layer, |
|
770 |
* the remaining elements are the parent layers in DFS order. |
|
771 |
* |
|
772 |
* @implNote For now, the assumption is that the number of elements will |
|
773 |
* be very low and so this method does not use a specialized spliterator. |
|
774 |
*/ |
|
775 |
Stream<ModuleLayer> layers() { |
|
776 |
List<ModuleLayer> allLayers = this.allLayers; |
|
777 |
if (allLayers != null) |
|
778 |
return allLayers.stream(); |
|
779 |
||
780 |
allLayers = new ArrayList<>(); |
|
781 |
Set<ModuleLayer> visited = new HashSet<>(); |
|
782 |
Deque<ModuleLayer> stack = new ArrayDeque<>(); |
|
783 |
visited.add(this); |
|
784 |
stack.push(this); |
|
785 |
||
786 |
while (!stack.isEmpty()) { |
|
787 |
ModuleLayer layer = stack.pop(); |
|
788 |
allLayers.add(layer); |
|
789 |
||
790 |
// push in reverse order |
|
791 |
for (int i = layer.parents.size() - 1; i >= 0; i--) { |
|
792 |
ModuleLayer parent = layer.parents.get(i); |
|
793 |
if (!visited.contains(parent)) { |
|
794 |
visited.add(parent); |
|
795 |
stack.push(parent); |
|
796 |
} |
|
797 |
} |
|
798 |
} |
|
799 |
||
800 |
this.allLayers = allLayers = Collections.unmodifiableList(allLayers); |
|
801 |
return allLayers.stream(); |
|
802 |
} |
|
803 |
||
804 |
private volatile List<ModuleLayer> allLayers; |
|
805 |
||
806 |
/** |
|
807 |
* Returns the set of the modules in this layer. |
|
808 |
* |
|
809 |
* @return A possibly-empty unmodifiable set of the modules in this layer |
|
810 |
*/ |
|
811 |
public Set<Module> modules() { |
|
812 |
Set<Module> modules = this.modules; |
|
813 |
if (modules == null) { |
|
814 |
this.modules = modules = |
|
815 |
Collections.unmodifiableSet(new HashSet<>(nameToModule.values())); |
|
816 |
} |
|
817 |
return modules; |
|
818 |
} |
|
819 |
||
820 |
private volatile Set<Module> modules; |
|
821 |
||
822 |
||
823 |
/** |
|
824 |
* Returns the module with the given name in this layer, or if not in this |
|
47004 | 825 |
* layer, the {@linkplain #parents() parent} layers. Finding a module in |
44545 | 826 |
* parent layers is equivalent to invoking {@code findModule} on each |
827 |
* parent, in search order, until the module is found or all parents have |
|
828 |
* been searched. In a <em>tree of layers</em> then this is equivalent to |
|
829 |
* a depth-first search. |
|
830 |
* |
|
831 |
* @param name |
|
832 |
* The name of the module to find |
|
833 |
* |
|
834 |
* @return The module with the given name or an empty {@code Optional} |
|
835 |
* if there isn't a module with this name in this layer or any |
|
836 |
* parent layer |
|
837 |
*/ |
|
838 |
public Optional<Module> findModule(String name) { |
|
839 |
Objects.requireNonNull(name); |
|
840 |
if (this == EMPTY_LAYER) |
|
841 |
return Optional.empty(); |
|
842 |
Module m = nameToModule.get(name); |
|
843 |
if (m != null) |
|
844 |
return Optional.of(m); |
|
845 |
||
846 |
return layers() |
|
847 |
.skip(1) // skip this layer |
|
848 |
.map(l -> l.nameToModule) |
|
849 |
.filter(map -> map.containsKey(name)) |
|
850 |
.map(map -> map.get(name)) |
|
851 |
.findAny(); |
|
852 |
} |
|
853 |
||
854 |
||
855 |
/** |
|
856 |
* Returns the {@code ClassLoader} for the module with the given name. If |
|
47004 | 857 |
* a module of the given name is not in this layer then the {@link #parents() |
44545 | 858 |
* parent} layers are searched in the manner specified by {@link |
859 |
* #findModule(String) findModule}. |
|
860 |
* |
|
861 |
* <p> If there is a security manager then its {@code checkPermission} |
|
862 |
* method is called with a {@code RuntimePermission("getClassLoader")} |
|
863 |
* permission to check that the caller is allowed to get access to the |
|
864 |
* class loader. </p> |
|
865 |
* |
|
866 |
* @apiNote This method does not return an {@code Optional<ClassLoader>} |
|
867 |
* because `null` must be used to represent the bootstrap class loader. |
|
868 |
* |
|
869 |
* @param name |
|
870 |
* The name of the module to find |
|
871 |
* |
|
872 |
* @return The ClassLoader that the module is defined to |
|
873 |
* |
|
874 |
* @throws IllegalArgumentException if a module of the given name is not |
|
875 |
* defined in this layer or any parent of this layer |
|
876 |
* |
|
877 |
* @throws SecurityException if denied by the security manager |
|
878 |
*/ |
|
879 |
public ClassLoader findLoader(String name) { |
|
880 |
Optional<Module> om = findModule(name); |
|
881 |
||
882 |
// can't use map(Module::getClassLoader) as class loader can be null |
|
883 |
if (om.isPresent()) { |
|
884 |
return om.get().getClassLoader(); |
|
885 |
} else { |
|
886 |
throw new IllegalArgumentException("Module " + name |
|
887 |
+ " not known to this layer"); |
|
888 |
} |
|
889 |
} |
|
890 |
||
891 |
/** |
|
892 |
* Returns a string describing this module layer. |
|
893 |
* |
|
894 |
* @return A possibly empty string describing this module layer |
|
895 |
*/ |
|
896 |
@Override |
|
897 |
public String toString() { |
|
898 |
return modules().stream() |
|
899 |
.map(Module::getName) |
|
900 |
.collect(Collectors.joining(", ")); |
|
901 |
} |
|
902 |
||
903 |
/** |
|
904 |
* Returns the <em>empty</em> layer. There are no modules in the empty |
|
905 |
* layer. It has no parents. |
|
906 |
* |
|
907 |
* @return The empty layer |
|
908 |
*/ |
|
909 |
public static ModuleLayer empty() { |
|
910 |
return EMPTY_LAYER; |
|
911 |
} |
|
912 |
||
913 |
||
914 |
/** |
|
915 |
* Returns the boot layer. The boot layer contains at least one module, |
|
916 |
* {@code java.base}. Its parent is the {@link #empty() empty} layer. |
|
917 |
* |
|
918 |
* @apiNote This method returns {@code null} during startup and before |
|
919 |
* the boot layer is fully initialized. |
|
920 |
* |
|
921 |
* @return The boot layer |
|
922 |
*/ |
|
923 |
public static ModuleLayer boot() { |
|
924 |
return System.bootLayer; |
|
925 |
} |
|
926 |
||
927 |
/** |
|
928 |
* Returns the ServicesCatalog for this Layer, creating it if not |
|
929 |
* already created. |
|
930 |
*/ |
|
931 |
ServicesCatalog getServicesCatalog() { |
|
932 |
ServicesCatalog servicesCatalog = this.servicesCatalog; |
|
933 |
if (servicesCatalog != null) |
|
934 |
return servicesCatalog; |
|
935 |
||
936 |
synchronized (this) { |
|
937 |
servicesCatalog = this.servicesCatalog; |
|
938 |
if (servicesCatalog == null) { |
|
939 |
servicesCatalog = ServicesCatalog.create(); |
|
940 |
nameToModule.values().forEach(servicesCatalog::register); |
|
941 |
this.servicesCatalog = servicesCatalog; |
|
942 |
} |
|
943 |
} |
|
944 |
||
945 |
return servicesCatalog; |
|
946 |
} |
|
947 |
||
948 |
private volatile ServicesCatalog servicesCatalog; |
|
949 |
||
950 |
||
951 |
/** |
|
952 |
* Record that this layer has at least one module defined to the given |
|
953 |
* class loader. |
|
954 |
*/ |
|
955 |
void bindToLoader(ClassLoader loader) { |
|
956 |
// CLV.computeIfAbsent(loader, (cl, clv) -> new CopyOnWriteArrayList<>()) |
|
957 |
List<ModuleLayer> list = CLV.get(loader); |
|
958 |
if (list == null) { |
|
959 |
list = new CopyOnWriteArrayList<>(); |
|
960 |
List<ModuleLayer> previous = CLV.putIfAbsent(loader, list); |
|
961 |
if (previous != null) list = previous; |
|
962 |
} |
|
963 |
list.add(this); |
|
964 |
} |
|
965 |
||
966 |
/** |
|
967 |
* Returns a stream of the layers that have at least one module defined to |
|
968 |
* the given class loader. |
|
969 |
*/ |
|
970 |
static Stream<ModuleLayer> layers(ClassLoader loader) { |
|
971 |
List<ModuleLayer> list = CLV.get(loader); |
|
972 |
if (list != null) { |
|
973 |
return list.stream(); |
|
974 |
} else { |
|
975 |
return Stream.empty(); |
|
976 |
} |
|
977 |
} |
|
978 |
||
979 |
// the list of layers with modules defined to a class loader |
|
980 |
private static final ClassLoaderValue<List<ModuleLayer>> CLV = new ClassLoaderValue<>(); |
|
981 |
} |