945 lines
37 KiB
Java
945 lines
37 KiB
Java
/*
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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 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 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 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
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*/
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public ModuleLayer defineModulesWithManyLoaders(Configuration cf,
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ClassLoader parentLoader) {
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return defineModulesWithManyLoaders(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 mapped, by name, to its class loader by means of the
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* given function. This method works exactly as specified by the static
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* {@link #defineModules(Configuration,List,Function) defineModules}
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* method when invoked with this layer as the parent. In other words, if
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* this layer is {@code thisLayer} then this method is equivalent to
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* invoking:
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* <pre> {@code
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* ModuleLayer.defineModules(cf, List.of(thisLayer), clf).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 clf
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* The function to map a module name to a 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 defineModules} method
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* @throws SecurityException
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* If {@code RuntimePermission("getClassLoader")} is denied by
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* the security manager
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*/
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public ModuleLayer defineModules(Configuration cf,
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Function<String, ClassLoader> clf) {
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return defineModules(cf, List.of(this), clf).layer();
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}
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/**
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* Creates a new module layer by defining the modules in the given {@code
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* Configuration} to the Java virtual machine. This method creates one
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* class loader and defines all modules to that class loader.
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*
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* <p> The class loader created by this method implements <em>direct
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* delegation</em> when loading types from modules. When its {@link
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* ClassLoader#loadClass(String, boolean) loadClass} method is invoked to
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* load a class then it uses the package name of the class to map it to a
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* module. This may be a module in this layer and hence defined to the same
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* class loader. It may be a package in a module in a parent layer that is
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* exported to one or more of the modules in this layer. The class
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* loader delegates to the class loader of the module, throwing {@code
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* ClassNotFoundException} if not found by that class loader.
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* When {@code loadClass} is invoked to load classes that do not map to a
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* module then it delegates to the parent class loader. </p>
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*
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* <p> Attempting to create a layer with all modules defined to the same
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* class loader can fail for the following reasons:
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*
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* <ul>
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*
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* <li><p> <em>Overlapping packages</em>: Two or more modules in the
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* configuration have the same package. </p></li>
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*
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* <li><p> <em>Split delegation</em>: The resulting class loader would
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* need to delegate to more than one class loader in order to load types
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* in a specific package. </p></li>
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*
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* </ul>
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*
|
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* <p> In addition, a layer cannot be created if the configuration contains
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* a module named "{@code java.base}", or a module contains a package named
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* "{@code java}" or a package with a name starting with "{@code java.}". </p>
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*
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* <p> If there is a security manager then the class loader created by
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* this method will load classes and resources with privileges that are
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* restricted by the calling context of this method. </p>
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*
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* @param cf
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* The configuration for the layer
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* @param parentLayers
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* The list of parent layers in search order
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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 A controller that controls the newly created layer
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*
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* @throws IllegalArgumentException
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* If the parent configurations do not match the configuration of
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* the parent layers, including order
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* @throws LayerInstantiationException
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* If all modules cannot be defined to the same class loader for any
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* of the reasons listed above
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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 static Controller defineModulesWithOneLoader(Configuration cf,
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List<ModuleLayer> parentLayers,
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ClassLoader parentLoader)
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{
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List<ModuleLayer> parents = new ArrayList<>(parentLayers);
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checkConfiguration(cf, parents);
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checkCreateClassLoaderPermission();
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checkGetClassLoaderPermission();
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try {
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Loader loader = new Loader(cf.modules(), parentLoader);
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loader.initRemotePackageMap(cf, parents);
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ModuleLayer layer = new ModuleLayer(cf, parents, mn -> loader);
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return new Controller(layer);
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} catch (IllegalArgumentException | IllegalStateException e) {
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throw new LayerInstantiationException(e.getMessage());
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}
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}
|
|
|
|
/**
|
|
* Creates a new module layer by defining the modules in the given {@code
|
|
* Configuration} to the Java virtual machine. Each module is defined to
|
|
* its own {@link ClassLoader} created by this method. The {@link
|
|
* ClassLoader#getParent() parent} of each class loader is the given parent
|
|
* class loader.
|
|
*
|
|
* <p> The class loaders created by this method implement <em>direct
|
|
* delegation</em> when loading types from modules. When {@link
|
|
* ClassLoader#loadClass(String, boolean) loadClass} method is invoked to
|
|
* load a class then it uses the package name of the class to map it to a
|
|
* module. The package may be in the module defined to the class loader.
|
|
* The package may be exported by another module in this layer to the
|
|
* module defined to the class loader. It may be in a package exported by a
|
|
* module in a parent layer. The class loader delegates to the class loader
|
|
* of the module, throwing {@code ClassNotFoundException} if not found by
|
|
* that class loader.
|
|
* When {@code loadClass} is invoked to load classes that do not map to a
|
|
* module then it delegates to the parent class loader. </p>
|
|
*
|
|
* <p> If there is a security manager then the class loaders created by
|
|
* this method will load classes and resources with privileges that are
|
|
* restricted by the calling context of this method. </p>
|
|
*
|
|
* @param cf
|
|
* The configuration for the layer
|
|
* @param parentLayers
|
|
* The list of parent layers in search order
|
|
* @param parentLoader
|
|
* The parent class loader for each of the class loaders created by
|
|
* this method; may be {@code null} for the bootstrap class loader
|
|
*
|
|
* @return A controller that controls the newly created layer
|
|
*
|
|
* @throws IllegalArgumentException
|
|
* If the parent configurations do not match the configuration of
|
|
* the parent layers, including order
|
|
* @throws LayerInstantiationException
|
|
* If the layer cannot be created because the configuration contains
|
|
* a module named "{@code java.base}" or a module contains a package
|
|
* named "{@code java}" or a package with a name starting with
|
|
* "{@code java.}"
|
|
*
|
|
* @throws SecurityException
|
|
* If {@code RuntimePermission("createClassLoader")} or
|
|
* {@code RuntimePermission("getClassLoader")} is denied by
|
|
* the security manager
|
|
*
|
|
* @see #findLoader
|
|
*/
|
|
public static Controller defineModulesWithManyLoaders(Configuration cf,
|
|
List<ModuleLayer> parentLayers,
|
|
ClassLoader parentLoader)
|
|
{
|
|
List<ModuleLayer> parents = new ArrayList<>(parentLayers);
|
|
checkConfiguration(cf, parents);
|
|
|
|
checkCreateClassLoaderPermission();
|
|
checkGetClassLoaderPermission();
|
|
|
|
LoaderPool pool = new LoaderPool(cf, parents, parentLoader);
|
|
try {
|
|
ModuleLayer layer = new ModuleLayer(cf, parents, pool::loaderFor);
|
|
return new Controller(layer);
|
|
} catch (IllegalArgumentException | IllegalStateException e) {
|
|
throw new LayerInstantiationException(e.getMessage());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Creates a new module layer by defining the modules in the given {@code
|
|
* Configuration} to the Java virtual machine. The given function maps each
|
|
* module in the configuration, by name, to a class loader. Creating the
|
|
* layer informs the Java virtual machine about the classes that may be
|
|
* loaded so that the Java virtual machine knows which module that each
|
|
* class is a member of.
|
|
*
|
|
* <p> The class loader delegation implemented by the class loaders must
|
|
* respect module readability. The class loaders should be
|
|
* {@link ClassLoader#registerAsParallelCapable parallel-capable} so as to
|
|
* avoid deadlocks during class loading. In addition, the entity creating
|
|
* a new layer with this method should arrange that the class loaders be
|
|
* ready to load from these modules before there are any attempts to load
|
|
* classes or resources. </p>
|
|
*
|
|
* <p> Creating a layer can fail for the following reasons: </p>
|
|
*
|
|
* <ul>
|
|
*
|
|
* <li><p> Two or more modules with the same package are mapped to the
|
|
* same class loader. </p></li>
|
|
*
|
|
* <li><p> A module is mapped to a class loader that already has a
|
|
* module of the same name defined to it. </p></li>
|
|
*
|
|
* <li><p> A module is mapped to a class loader that has already
|
|
* defined types in any of the packages in the module. </p></li>
|
|
*
|
|
* </ul>
|
|
*
|
|
* <p> In addition, a layer cannot be created if the configuration contains
|
|
* a module named "{@code java.base}", a configuration contains a module
|
|
* with a package named "{@code java}" or a package name starting with
|
|
* "{@code java.}" and the module is mapped to a class loader other than
|
|
* the {@link ClassLoader#getPlatformClassLoader() platform class loader},
|
|
* or the function to map a module name to a class loader returns
|
|
* {@code null}. </p>
|
|
*
|
|
* <p> If the function to map a module name to class loader throws an error
|
|
* or runtime exception then it is propagated to the caller of this method.
|
|
* </p>
|
|
*
|
|
* @apiNote It is implementation specific as to whether creating a layer
|
|
* with this method is an atomic operation or not. Consequentially it is
|
|
* possible for this method to fail with some modules, but not all, defined
|
|
* to the Java virtual machine.
|
|
*
|
|
* @param cf
|
|
* The configuration for the layer
|
|
* @param parentLayers
|
|
* The list of parent layers in search order
|
|
* @param clf
|
|
* The function to map a module name to a class loader
|
|
*
|
|
* @return A controller that controls the newly created layer
|
|
*
|
|
* @throws IllegalArgumentException
|
|
* If the parent configurations do not match the configuration of
|
|
* the parent layers, including order
|
|
* @throws LayerInstantiationException
|
|
* If creating the layer fails for any of the reasons listed above
|
|
* @throws SecurityException
|
|
* If {@code RuntimePermission("getClassLoader")} is denied by
|
|
* the security manager
|
|
*/
|
|
public static Controller defineModules(Configuration cf,
|
|
List<ModuleLayer> parentLayers,
|
|
Function<String, ClassLoader> clf)
|
|
{
|
|
List<ModuleLayer> parents = new ArrayList<>(parentLayers);
|
|
checkConfiguration(cf, parents);
|
|
Objects.requireNonNull(clf);
|
|
|
|
checkGetClassLoaderPermission();
|
|
|
|
// The boot layer is checked during module system initialization
|
|
if (boot() != null) {
|
|
checkForDuplicatePkgs(cf, clf);
|
|
}
|
|
|
|
try {
|
|
ModuleLayer layer = new ModuleLayer(cf, parents, clf);
|
|
return new Controller(layer);
|
|
} catch (IllegalArgumentException | IllegalStateException e) {
|
|
throw new LayerInstantiationException(e.getMessage());
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Checks that the parent configurations match the configuration of
|
|
* the parent layers.
|
|
*/
|
|
private static void checkConfiguration(Configuration cf,
|
|
List<ModuleLayer> parentLayers)
|
|
{
|
|
Objects.requireNonNull(cf);
|
|
|
|
List<Configuration> parentConfigurations = cf.parents();
|
|
if (parentLayers.size() != parentConfigurations.size())
|
|
throw new IllegalArgumentException("wrong number of parents");
|
|
|
|
int index = 0;
|
|
for (ModuleLayer parent : parentLayers) {
|
|
if (parent.configuration() != parentConfigurations.get(index)) {
|
|
throw new IllegalArgumentException(
|
|
"Parent of configuration != configuration of this Layer");
|
|
}
|
|
index++;
|
|
}
|
|
}
|
|
|
|
private static void checkCreateClassLoaderPermission() {
|
|
SecurityManager sm = System.getSecurityManager();
|
|
if (sm != null)
|
|
sm.checkPermission(SecurityConstants.CREATE_CLASSLOADER_PERMISSION);
|
|
}
|
|
|
|
private static void checkGetClassLoaderPermission() {
|
|
SecurityManager sm = System.getSecurityManager();
|
|
if (sm != null)
|
|
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
|
|
}
|
|
|
|
/**
|
|
* Checks a configuration and the module-to-loader mapping to ensure that
|
|
* no two modules mapped to the same class loader have the same package.
|
|
* It also checks that no two automatic modules have the same package.
|
|
*
|
|
* @throws LayerInstantiationException
|
|
*/
|
|
private static void checkForDuplicatePkgs(Configuration cf,
|
|
Function<String, ClassLoader> clf)
|
|
{
|
|
// HashMap allows null keys
|
|
Map<ClassLoader, Set<String>> loaderToPackages = new HashMap<>();
|
|
for (ResolvedModule resolvedModule : cf.modules()) {
|
|
ModuleDescriptor descriptor = resolvedModule.reference().descriptor();
|
|
ClassLoader loader = clf.apply(descriptor.name());
|
|
|
|
Set<String> loaderPackages
|
|
= loaderToPackages.computeIfAbsent(loader, k -> new HashSet<>());
|
|
|
|
for (String pkg : descriptor.packages()) {
|
|
boolean added = loaderPackages.add(pkg);
|
|
if (!added) {
|
|
throw fail("More than one module with package %s mapped" +
|
|
" to the same class loader", pkg);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Creates a LayerInstantiationException with the a message formatted from
|
|
* the given format string and arguments.
|
|
*/
|
|
private static LayerInstantiationException fail(String fmt, Object ... args) {
|
|
String msg = String.format(fmt, args);
|
|
return new LayerInstantiationException(msg);
|
|
}
|
|
|
|
|
|
/**
|
|
* Returns the configuration for this layer.
|
|
*
|
|
* @return The configuration for this layer
|
|
*/
|
|
public Configuration configuration() {
|
|
return cf;
|
|
}
|
|
|
|
|
|
/**
|
|
* Returns the list of this layer's parents unless this is the
|
|
* {@linkplain #empty empty layer}, which has no parents and so an
|
|
* empty list is returned.
|
|
*
|
|
* @return The list of this layer's parents
|
|
*/
|
|
public List<ModuleLayer> parents() {
|
|
return parents;
|
|
}
|
|
|
|
|
|
/**
|
|
* Returns an ordered stream of layers. The first element is is this layer,
|
|
* the remaining elements are the parent layers in DFS order.
|
|
*
|
|
* @implNote For now, the assumption is that the number of elements will
|
|
* be very low and so this method does not use a specialized spliterator.
|
|
*/
|
|
Stream<ModuleLayer> layers() {
|
|
List<ModuleLayer> allLayers = this.allLayers;
|
|
if (allLayers != null)
|
|
return allLayers.stream();
|
|
|
|
allLayers = new ArrayList<>();
|
|
Set<ModuleLayer> visited = new HashSet<>();
|
|
Deque<ModuleLayer> stack = new ArrayDeque<>();
|
|
visited.add(this);
|
|
stack.push(this);
|
|
|
|
while (!stack.isEmpty()) {
|
|
ModuleLayer layer = stack.pop();
|
|
allLayers.add(layer);
|
|
|
|
// push in reverse order
|
|
for (int i = layer.parents.size() - 1; i >= 0; i--) {
|
|
ModuleLayer parent = layer.parents.get(i);
|
|
if (!visited.contains(parent)) {
|
|
visited.add(parent);
|
|
stack.push(parent);
|
|
}
|
|
}
|
|
}
|
|
|
|
this.allLayers = allLayers = Collections.unmodifiableList(allLayers);
|
|
return allLayers.stream();
|
|
}
|
|
|
|
private volatile List<ModuleLayer> allLayers;
|
|
|
|
/**
|
|
* Returns the set of the modules in this layer.
|
|
*
|
|
* @return A possibly-empty unmodifiable set of the modules in this layer
|
|
*/
|
|
public Set<Module> modules() {
|
|
Set<Module> modules = this.modules;
|
|
if (modules == null) {
|
|
this.modules = modules =
|
|
Collections.unmodifiableSet(new HashSet<>(nameToModule.values()));
|
|
}
|
|
return modules;
|
|
}
|
|
|
|
private volatile Set<Module> modules;
|
|
|
|
|
|
/**
|
|
* Returns the module with the given name in this layer, or if not in this
|
|
* layer, the {@linkplain #parents parent} layers. Finding a module in
|
|
* parent layers is equivalent to invoking {@code findModule} on each
|
|
* parent, in search order, until the module is found or all parents have
|
|
* been searched. In a <em>tree of layers</em> then this is equivalent to
|
|
* a depth-first search.
|
|
*
|
|
* @param name
|
|
* The name of the module to find
|
|
*
|
|
* @return The module with the given name or an empty {@code Optional}
|
|
* if there isn't a module with this name in this layer or any
|
|
* parent layer
|
|
*/
|
|
public Optional<Module> findModule(String name) {
|
|
Objects.requireNonNull(name);
|
|
if (this == EMPTY_LAYER)
|
|
return Optional.empty();
|
|
Module m = nameToModule.get(name);
|
|
if (m != null)
|
|
return Optional.of(m);
|
|
|
|
return layers()
|
|
.skip(1) // skip this layer
|
|
.map(l -> l.nameToModule)
|
|
.filter(map -> map.containsKey(name))
|
|
.map(map -> map.get(name))
|
|
.findAny();
|
|
}
|
|
|
|
|
|
/**
|
|
* Returns the {@code ClassLoader} for the module with the given name. If
|
|
* a module of the given name is not in this layer then the {@link #parents
|
|
* parent} layers are searched in the manner specified by {@link
|
|
* #findModule(String) findModule}.
|
|
*
|
|
* <p> If there is a security manager then its {@code checkPermission}
|
|
* method is called with a {@code RuntimePermission("getClassLoader")}
|
|
* permission to check that the caller is allowed to get access to the
|
|
* class loader. </p>
|
|
*
|
|
* @apiNote This method does not return an {@code Optional<ClassLoader>}
|
|
* because `null` must be used to represent the bootstrap class loader.
|
|
*
|
|
* @param name
|
|
* The name of the module to find
|
|
*
|
|
* @return The ClassLoader that the module is defined to
|
|
*
|
|
* @throws IllegalArgumentException if a module of the given name is not
|
|
* defined in this layer or any parent of this layer
|
|
*
|
|
* @throws SecurityException if denied by the security manager
|
|
*/
|
|
public ClassLoader findLoader(String name) {
|
|
Optional<Module> om = findModule(name);
|
|
|
|
// can't use map(Module::getClassLoader) as class loader can be null
|
|
if (om.isPresent()) {
|
|
return om.get().getClassLoader();
|
|
} else {
|
|
throw new IllegalArgumentException("Module " + name
|
|
+ " not known to this layer");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a string describing this module layer.
|
|
*
|
|
* @return A possibly empty string describing this module layer
|
|
*/
|
|
@Override
|
|
public String toString() {
|
|
return modules().stream()
|
|
.map(Module::getName)
|
|
.collect(Collectors.joining(", "));
|
|
}
|
|
|
|
/**
|
|
* Returns the <em>empty</em> layer. There are no modules in the empty
|
|
* layer. It has no parents.
|
|
*
|
|
* @return The empty layer
|
|
*/
|
|
public static ModuleLayer empty() {
|
|
return EMPTY_LAYER;
|
|
}
|
|
|
|
|
|
/**
|
|
* Returns the boot layer. The boot layer contains at least one module,
|
|
* {@code java.base}. Its parent is the {@link #empty() empty} layer.
|
|
*
|
|
* @apiNote This method returns {@code null} during startup and before
|
|
* the boot layer is fully initialized.
|
|
*
|
|
* @return The boot layer
|
|
*/
|
|
public static ModuleLayer boot() {
|
|
return System.bootLayer;
|
|
}
|
|
|
|
/**
|
|
* Returns the ServicesCatalog for this Layer, creating it if not
|
|
* already created.
|
|
*/
|
|
ServicesCatalog getServicesCatalog() {
|
|
ServicesCatalog servicesCatalog = this.servicesCatalog;
|
|
if (servicesCatalog != null)
|
|
return servicesCatalog;
|
|
|
|
synchronized (this) {
|
|
servicesCatalog = this.servicesCatalog;
|
|
if (servicesCatalog == null) {
|
|
servicesCatalog = ServicesCatalog.create();
|
|
nameToModule.values().forEach(servicesCatalog::register);
|
|
this.servicesCatalog = servicesCatalog;
|
|
}
|
|
}
|
|
|
|
return servicesCatalog;
|
|
}
|
|
|
|
private volatile ServicesCatalog servicesCatalog;
|
|
|
|
|
|
/**
|
|
* Record that this layer has at least one module defined to the given
|
|
* class loader.
|
|
*/
|
|
void bindToLoader(ClassLoader loader) {
|
|
// CLV.computeIfAbsent(loader, (cl, clv) -> new CopyOnWriteArrayList<>())
|
|
List<ModuleLayer> list = CLV.get(loader);
|
|
if (list == null) {
|
|
list = new CopyOnWriteArrayList<>();
|
|
List<ModuleLayer> previous = CLV.putIfAbsent(loader, list);
|
|
if (previous != null) list = previous;
|
|
}
|
|
list.add(this);
|
|
}
|
|
|
|
/**
|
|
* Returns a stream of the layers that have at least one module defined to
|
|
* the given class loader.
|
|
*/
|
|
static Stream<ModuleLayer> layers(ClassLoader loader) {
|
|
List<ModuleLayer> list = CLV.get(loader);
|
|
if (list != null) {
|
|
return list.stream();
|
|
} else {
|
|
return Stream.empty();
|
|
}
|
|
}
|
|
|
|
// the list of layers with modules defined to a class loader
|
|
private static final ClassLoaderValue<List<ModuleLayer>> CLV = new ClassLoaderValue<>();
|
|
}
|