| /* |
| * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.lang; |
| |
| import java.lang.module.Configuration; |
| import java.lang.module.ModuleDescriptor; |
| import java.lang.module.ResolvedModule; |
| import java.util.ArrayDeque; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.Deque; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Objects; |
| import java.util.Optional; |
| import java.util.Set; |
| import java.util.concurrent.CopyOnWriteArrayList; |
| import java.util.function.Function; |
| import java.util.stream.Collectors; |
| import java.util.stream.Stream; |
| |
| import jdk.internal.loader.ClassLoaderValue; |
| import jdk.internal.loader.Loader; |
| import jdk.internal.loader.LoaderPool; |
| import jdk.internal.module.ServicesCatalog; |
| import sun.security.util.SecurityConstants; |
| |
| |
| /** |
| * A layer of modules in the Java virtual machine. |
| * |
| * <p> A layer is created from a graph of modules in a {@link Configuration} |
| * and a function that maps each module to a {@link ClassLoader}. |
| * Creating a layer informs the Java virtual machine about the classes that |
| * may be loaded from the modules so that the Java virtual machine knows which |
| * module that each class is a member of. </p> |
| * |
| * <p> Creating a layer creates a {@link Module} object for each {@link |
| * ResolvedModule} in the configuration. For each resolved module that is |
| * {@link ResolvedModule#reads() read}, the {@code Module} {@link |
| * Module#canRead reads} the corresponding run-time {@code Module}, which may |
| * be in the same layer or a {@link #parents() parent} layer. </p> |
| * |
| * <p> The {@link #defineModulesWithOneLoader defineModulesWithOneLoader} and |
| * {@link #defineModulesWithManyLoaders defineModulesWithManyLoaders} methods |
| * provide convenient ways to create a module layer where all modules are |
| * mapped to a single class loader or where each module is mapped to its own |
| * class loader. The {@link #defineModules defineModules} method is for more |
| * advanced cases where modules are mapped to custom class loaders by means of |
| * a function specified to the method. Each of these methods has an instance |
| * and static variant. The instance methods create a layer with the receiver |
| * as the parent layer. The static methods are for more advanced cases where |
| * there can be more than one parent layer or where a {@link |
| * ModuleLayer.Controller Controller} is needed to control modules in the layer |
| * </p> |
| * |
| * <p> A Java virtual machine has at least one non-empty layer, the {@link |
| * #boot() boot} layer, that is created when the Java virtual machine is |
| * started. The boot layer contains module {@code java.base} and is the only |
| * layer in the Java virtual machine with a module named "{@code java.base}". |
| * The modules in the boot layer are mapped to the bootstrap class loader and |
| * other class loaders that are <a href="ClassLoader.html#builtinLoaders"> |
| * built-in</a> into the Java virtual machine. The boot layer will often be |
| * the {@link #parents() parent} when creating additional layers. </p> |
| * |
| * <p> Each {@code Module} in a layer is created so that it {@link |
| * Module#isExported(String) exports} and {@link Module#isOpen(String) opens} |
| * the packages described by its {@link ModuleDescriptor}. Qualified exports |
| * (where a package is exported to a set of target modules rather than all |
| * modules) are reified when creating the layer as follows: </p> |
| * <ul> |
| * <li> If module {@code X} exports a package to {@code Y}, and if the |
| * runtime {@code Module} {@code X} reads {@code Module} {@code Y}, then |
| * the package is exported to {@code Module} {@code Y} (which may be in |
| * the same layer as {@code X} or a parent layer). </li> |
| * |
| * <li> If module {@code X} exports a package to {@code Y}, and if the |
| * runtime {@code Module} {@code X} does not read {@code Y} then target |
| * {@code Y} is located as if by invoking {@link #findModule(String) |
| * findModule} to find the module in the layer or its parent layers. If |
| * {@code Y} is found then the package is exported to the instance of |
| * {@code Y} that was found. If {@code Y} is not found then the qualified |
| * export is ignored. </li> |
| * </ul> |
| * |
| * <p> Qualified opens are handled in same way as qualified exports. </p> |
| * |
| * <p> As when creating a {@code Configuration}, |
| * {@link ModuleDescriptor#isAutomatic() automatic} modules receive special |
| * treatment when creating a layer. An automatic module is created in the |
| * Java virtual machine as a {@code Module} that reads every unnamed {@code |
| * Module} in the Java virtual machine. </p> |
| * |
| * <p> Unless otherwise specified, passing a {@code null} argument to a method |
| * in this class causes a {@link NullPointerException NullPointerException} to |
| * be thrown. </p> |
| * |
| * <h3> Example usage: </h3> |
| * |
| * <p> This example creates a configuration by resolving a module named |
| * "{@code myapp}" with the configuration for the boot layer as the parent. It |
| * then creates a new layer with the modules in this configuration. All modules |
| * are defined to the same class loader. </p> |
| * |
| * <pre>{@code |
| * ModuleFinder finder = ModuleFinder.of(dir1, dir2, dir3); |
| * |
| * ModuleLayer parent = ModuleLayer.boot(); |
| * |
| * Configuration cf = parent.configuration().resolve(finder, ModuleFinder.of(), Set.of("myapp")); |
| * |
| * ClassLoader scl = ClassLoader.getSystemClassLoader(); |
| * |
| * ModuleLayer layer = parent.defineModulesWithOneLoader(cf, scl); |
| * |
| * Class<?> c = layer.findLoader("myapp").loadClass("app.Main"); |
| * }</pre> |
| * |
| * @since 9 |
| * @spec JPMS |
| * @see Module#getLayer() |
| */ |
| |
| public final class ModuleLayer { |
| |
| // the empty layer |
| private static final ModuleLayer EMPTY_LAYER |
| = new ModuleLayer(Configuration.empty(), List.of(), null); |
| |
| // the configuration from which this layer was created |
| private final Configuration cf; |
| |
| // parent layers, empty in the case of the empty layer |
| private final List<ModuleLayer> parents; |
| |
| // maps module name to jlr.Module |
| private final Map<String, Module> nameToModule; |
| |
| /** |
| * Creates a new module layer from the modules in the given configuration. |
| */ |
| private ModuleLayer(Configuration cf, |
| List<ModuleLayer> parents, |
| Function<String, ClassLoader> clf) |
| { |
| this.cf = cf; |
| this.parents = parents; // no need to do defensive copy |
| |
| Map<String, Module> map; |
| if (parents.isEmpty()) { |
| map = Map.of(); |
| } else { |
| map = Module.defineModules(cf, clf, this); |
| } |
| this.nameToModule = map; // no need to do defensive copy |
| } |
| |
| /** |
| * Controls a module layer. The static methods defined by {@link ModuleLayer} |
| * to create module layers return a {@code Controller} that can be used to |
| * control modules in the layer. |
| * |
| * <p> Unless otherwise specified, passing a {@code null} argument to a |
| * method in this class causes a {@link NullPointerException |
| * NullPointerException} to be thrown. </p> |
| * |
| * @apiNote Care should be taken with {@code Controller} objects, they |
| * should never be shared with untrusted code. |
| * |
| * @since 9 |
| * @spec JPMS |
| */ |
| public static final class Controller { |
| private final ModuleLayer layer; |
| |
| Controller(ModuleLayer layer) { |
| this.layer = layer; |
| } |
| |
| /** |
| * Returns the layer that this object controls. |
| * |
| * @return the module layer |
| */ |
| public ModuleLayer layer() { |
| return layer; |
| } |
| |
| private void ensureInLayer(Module source) { |
| if (source.getLayer() != layer) |
| throw new IllegalArgumentException(source + " not in layer"); |
| } |
| |
| |
| /** |
| * Updates module {@code source} in the layer to read module |
| * {@code target}. This method is a no-op if {@code source} already |
| * reads {@code target}. |
| * |
| * @implNote <em>Read edges</em> added by this method are <em>weak</em> |
| * and do not prevent {@code target} from being GC'ed when {@code source} |
| * is strongly reachable. |
| * |
| * @param source |
| * The source module |
| * @param target |
| * The target module to read |
| * |
| * @return This controller |
| * |
| * @throws IllegalArgumentException |
| * If {@code source} is not in the module layer |
| * |
| * @see Module#addReads |
| */ |
| public Controller addReads(Module source, Module target) { |
| ensureInLayer(source); |
| source.implAddReads(target); |
| return this; |
| } |
| |
| /** |
| * Updates module {@code source} in the layer to export a package to |
| * module {@code target}. This method is a no-op if {@code source} |
| * already exports the package to at least {@code target}. |
| * |
| * @param source |
| * The source module |
| * @param pn |
| * The package name |
| * @param target |
| * The target module |
| * |
| * @return This controller |
| * |
| * @throws IllegalArgumentException |
| * If {@code source} is not in the module layer or the package |
| * is not in the source module |
| * |
| * @see Module#addExports |
| */ |
| public Controller addExports(Module source, String pn, Module target) { |
| ensureInLayer(source); |
| source.implAddExports(pn, target); |
| return this; |
| } |
| |
| /** |
| * Updates module {@code source} in the layer to open a package to |
| * module {@code target}. This method is a no-op if {@code source} |
| * already opens the package to at least {@code target}. |
| * |
| * @param source |
| * The source module |
| * @param pn |
| * The package name |
| * @param target |
| * The target module |
| * |
| * @return This controller |
| * |
| * @throws IllegalArgumentException |
| * If {@code source} is not in the module layer or the package |
| * is not in the source module |
| * |
| * @see Module#addOpens |
| */ |
| public Controller addOpens(Module source, String pn, Module target) { |
| ensureInLayer(source); |
| source.implAddOpens(pn, target); |
| return this; |
| } |
| } |
| |
| |
| /** |
| * Creates a new module layer, with this layer as its parent, by defining the |
| * modules in the given {@code Configuration} to the Java virtual machine. |
| * This method creates one class loader and defines all modules to that |
| * class loader. The {@link ClassLoader#getParent() parent} of each class |
| * loader is the given parent class loader. This method works exactly as |
| * specified by the static {@link |
| * #defineModulesWithOneLoader(Configuration,List,ClassLoader) |
| * defineModulesWithOneLoader} method when invoked with this layer as the |
| * parent. In other words, if this layer is {@code thisLayer} then this |
| * method is equivalent to invoking: |
| * <pre> {@code |
| * ModuleLayer.defineModulesWithOneLoader(cf, List.of(thisLayer), parentLoader).layer(); |
| * }</pre> |
| * |
| * @param cf |
| * The configuration for the layer |
| * @param parentLoader |
| * The parent class loader for the class loader created by this |
| * method; may be {@code null} for the bootstrap class loader |
| * |
| * @return The newly created layer |
| * |
| * @throws IllegalArgumentException |
| * If the given configuration has more than one parent or the parent |
| * of the configuration is not the configuration for this layer |
| * @throws LayerInstantiationException |
| * If the layer cannot be created for any of the reasons specified |
| * by the static {@code defineModulesWithOneLoader} method |
| * @throws SecurityException |
| * If {@code RuntimePermission("createClassLoader")} or |
| * {@code RuntimePermission("getClassLoader")} is denied by |
| * the security manager |
| * |
| * @see #findLoader |
| */ |
| public ModuleLayer defineModulesWithOneLoader(Configuration cf, |
| ClassLoader parentLoader) { |
| return defineModulesWithOneLoader(cf, List.of(this), parentLoader).layer(); |
| } |
| |
| |
| /** |
| * Creates a new module layer, with this layer as its parent, 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. This method works exactly as specified |
| * by the static {@link |
| * #defineModulesWithManyLoaders(Configuration,List,ClassLoader) |
| * defineModulesWithManyLoaders} method when invoked with this layer as the |
| * parent. In other words, if this layer is {@code thisLayer} then this |
| * method is equivalent to invoking: |
| * <pre> {@code |
| * ModuleLayer.defineModulesWithManyLoaders(cf, List.of(thisLayer), parentLoader).layer(); |
| * }</pre> |
| * |
| * @param cf |
| * The configuration for the layer |
| * @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 The newly created layer |
| * |
| * @throws IllegalArgumentException |
| * If the given configuration has more than one parent or the parent |
| * of the configuration is not the configuration for this layer |
| * @throws LayerInstantiationException |
| * If the layer cannot be created for any of the reasons specified |
| * by the static {@code defineModulesWithManyLoaders} method |
| * @throws SecurityException |
| * If {@code RuntimePermission("createClassLoader")} or |
| * {@code RuntimePermission("getClassLoader")} is denied by |
| * the security manager |
| * |
| * @see #findLoader |
| */ |
| public ModuleLayer defineModulesWithManyLoaders(Configuration cf, |
| ClassLoader parentLoader) { |
| return defineModulesWithManyLoaders(cf, List.of(this), parentLoader).layer(); |
| } |
| |
| |
| /** |
| * Creates a new module layer, with this layer as its parent, by defining the |
| * modules in the given {@code Configuration} to the Java virtual machine. |
| * Each module is mapped, by name, to its class loader by means of the |
| * given function. This method works exactly as specified by the static |
| * {@link #defineModules(Configuration,List,Function) defineModules} |
| * method when invoked with this layer as the parent. In other words, if |
| * this layer is {@code thisLayer} then this method is equivalent to |
| * invoking: |
| * <pre> {@code |
| * ModuleLayer.defineModules(cf, List.of(thisLayer), clf).layer(); |
| * }</pre> |
| * |
| * @param cf |
| * The configuration for the layer |
| * @param clf |
| * The function to map a module name to a class loader |
| * |
| * @return The newly created layer |
| * |
| * @throws IllegalArgumentException |
| * If the given configuration has more than one parent or the parent |
| * of the configuration is not the configuration for this layer |
| * @throws LayerInstantiationException |
| * If the layer cannot be created for any of the reasons specified |
| * by the static {@code defineModules} method |
| * @throws SecurityException |
| * If {@code RuntimePermission("getClassLoader")} is denied by |
| * the security manager |
| */ |
| public ModuleLayer defineModules(Configuration cf, |
| Function<String, ClassLoader> clf) { |
| return defineModules(cf, List.of(this), clf).layer(); |
| } |
| |
| /** |
| * Creates a new module layer by defining the modules in the given {@code |
| * Configuration} to the Java virtual machine. This method creates one |
| * class loader and defines all modules to that class loader. |
| * |
| * <p> The class loader created by this method implements <em>direct |
| * delegation</em> when loading classes from modules. If the {@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. This may be a module in this layer and hence defined to the same |
| * class loader. It may be a package in a module in a parent layer that is |
| * exported to one or more of the modules in this 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> The class loader created by this method locates resources |
| * ({@link ClassLoader#getResource(String) getResource}, {@link |
| * ClassLoader#getResources(String) getResources}, and other resource |
| * methods) in all modules in the layer before searching the parent class |
| * loader. </p> |
| * |
| * <p> Attempting to create a layer with all modules defined to the same |
| * class loader can fail for the following reasons: |
| * |
| * <ul> |
| * |
| * <li><p> <em>Overlapping packages</em>: Two or more modules in the |
| * configuration have the same package. </p></li> |
| * |
| * <li><p> <em>Split delegation</em>: The resulting class loader would |
| * need to delegate to more than one class loader in order to load |
| * classes in a specific package. </p></li> |
| * |
| * </ul> |
| * |
| * <p> In addition, a layer cannot be created if 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.}". </p> |
| * |
| * <p> If there is a security manager then the class loader 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 the class loader 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(s) of the given configuration do not match the |
| * configuration of the parent layers, including order |
| * @throws LayerInstantiationException |
| * If all modules cannot be defined to the same class loader for any |
| * of the reasons listed above |
| * @throws SecurityException |
| * If {@code RuntimePermission("createClassLoader")} or |
| * {@code RuntimePermission("getClassLoader")} is denied by |
| * the security manager |
| * |
| * @see #findLoader |
| */ |
| public static Controller defineModulesWithOneLoader(Configuration cf, |
| List<ModuleLayer> parentLayers, |
| ClassLoader parentLoader) |
| { |
| List<ModuleLayer> parents = new ArrayList<>(parentLayers); |
| checkConfiguration(cf, parents); |
| |
| checkCreateClassLoaderPermission(); |
| checkGetClassLoaderPermission(); |
| |
| try { |
| Loader loader = new Loader(cf.modules(), parentLoader); |
| loader.initRemotePackageMap(cf, parents); |
| ModuleLayer layer = new ModuleLayer(cf, parents, mn -> loader); |
| 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. 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 classes from modules. If the {@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 a class |
| * that does not map to a module then it delegates to the parent class |
| * loader. </p> |
| * |
| * <p> The class loaders created by this method locate resources |
| * ({@link ClassLoader#getResource(String) getResource}, {@link |
| * ClassLoader#getResources(String) getResources}, and other resource |
| * methods) in the module defined to the class loader before searching |
| * 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(s) of the given configuration 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.}", or the function to map a module name to a class loader |
| * returns {@code null} or the {@linkplain ClassLoader#getPlatformClassLoader() |
| * platform class loader}. </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(s) of the given configuration 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 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 = Set.copyOf(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.get(name)) |
| .filter(Objects::nonNull) |
| .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<>(); |
| } |
