net.bytebuddy.utility.JavaModule Maven / Gradle / Ivy
/*
* Copyright 2014 - Present Rafael Winterhalter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.bytebuddy.utility;
import net.bytebuddy.ClassFileVersion;
import net.bytebuddy.build.AccessControllerPlugin;
import net.bytebuddy.description.NamedElement;
import net.bytebuddy.description.annotation.AnnotationList;
import net.bytebuddy.description.annotation.AnnotationSource;
import net.bytebuddy.description.type.PackageDescription;
import net.bytebuddy.utility.dispatcher.JavaDispatcher;
import net.bytebuddy.utility.nullability.AlwaysNull;
import net.bytebuddy.utility.nullability.MaybeNull;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.AnnotatedElement;
import java.security.PrivilegedAction;
/**
* Type-safe representation of a {@code java.lang.Module}. On platforms that do not support the module API, modules are represented by {@code null}.
*/
public class JavaModule implements NamedElement.WithOptionalName, AnnotationSource {
/**
* Canonical representation of a Java module on a JVM that does not support the module API.
*/
@AlwaysNull
public static final JavaModule UNSUPPORTED = null;
/**
* A dispatcher to resolve a {@link Class}'s {@code java.lang.Module}.
*/
protected static final Resolver RESOLVER = doPrivileged(JavaDispatcher.of(Resolver.class));
/**
* A dispatcher to interact with {@code java.lang.Module}.
*/
protected static final Module MODULE = doPrivileged(JavaDispatcher.of(Module.class));
/**
* The {@code java.lang.Module} instance this wrapper represents.
*/
private final AnnotatedElement module;
/**
* Creates a new Java module representation.
*
* @param module The {@code java.lang.Module} instance this wrapper represents.
*/
protected JavaModule(AnnotatedElement module) {
this.module = module;
}
/**
* A proxy for {@code java.security.AccessController#doPrivileged} that is activated if available.
*
* @param action The action to execute from a privileged context.
* @param The type of the action's resolved value.
* @return The action's resolved value.
*/
@AccessControllerPlugin.Enhance
private static T doPrivileged(PrivilegedAction action) {
return action.run();
}
/**
* Returns a representation of the supplied type's {@code java.lang.Module} or {@code null} if the current VM does not support modules.
*
* @param type The type for which to describe the module.
* @return A representation of the type's module or {@code null} if the current VM does not support modules.
*/
@MaybeNull
public static JavaModule ofType(Class type) {
Object module = RESOLVER.getModule(type);
return module == null
? UNSUPPORTED
: new JavaModule((AnnotatedElement) module);
}
/**
* Represents the supplied {@code java.lang.Module} as an instance of this class and validates that the
* supplied instance really represents a Java {@code Module}.
*
* @param module The module to represent.
* @return A representation of the supplied Java module.
*/
public static JavaModule of(Object module) {
if (!MODULE.isInstance(module)) {
throw new IllegalArgumentException("Not a Java module: " + module);
}
return new JavaModule((AnnotatedElement) module);
}
/**
* Checks if the current VM supports the {@code java.lang.Module} API.
*
* @return {@code true} if the current VM supports modules.
*/
public static boolean isSupported() {
return ClassFileVersion.ofThisVm(ClassFileVersion.JAVA_V5).isAtLeast(ClassFileVersion.JAVA_V9);
}
/**
* {@inheritDoc}
*/
public boolean isNamed() {
return MODULE.isNamed(module);
}
/**
* {@inheritDoc}
*/
public String getActualName() {
return MODULE.getName(module);
}
/**
* Returns a resource stream for this module for a resource of the given name or {@code null} if such a resource does not exist.
*
* @param name The name of the resource.
* @return An input stream for the resource or {@code null} if it does not exist.
* @throws IOException If an I/O exception occurs.
*/
@MaybeNull
public InputStream getResourceAsStream(String name) throws IOException {
return MODULE.getResourceAsStream(module, name);
}
/**
* Returns the class loader of this module.
*
* @return The class loader of the represented module.
*/
@MaybeNull
public ClassLoader getClassLoader() {
return MODULE.getClassLoader(module);
}
/**
* Unwraps this instance to a {@code java.lang.Module}.
*
* @return The represented {@code java.lang.Module}.
*/
public Object unwrap() {
return module;
}
/**
* Checks if this module can read the exported packages of the supplied module.
*
* @param module The module to check for its readability by this module.
* @return {@code true} if this module can read the supplied module.
*/
public boolean canRead(JavaModule module) {
return MODULE.canRead(this.module, module.unwrap());
}
/**
* Returns {@code true} if this module exports the supplied package to this module.
*
* @param packageDescription The package to check for
* @param module The target module.
* @return {@code true} if this module exports the supplied package to this module.
*/
public boolean isExported(@MaybeNull PackageDescription packageDescription, JavaModule module) {
return packageDescription == null || MODULE.isExported(this.module, packageDescription.getName(), module.unwrap());
}
/**
* Returns {@code true} if this module opens the supplied package to this module.
*
* @param packageDescription The package to check for.
* @param module The target module.
* @return {@code true} if this module opens the supplied package to this module.
*/
public boolean isOpened(@MaybeNull PackageDescription packageDescription, JavaModule module) {
return packageDescription == null || MODULE.isOpen(this.module, packageDescription.getName(), module.unwrap());
}
/**
* {@inheritDoc}
*/
public AnnotationList getDeclaredAnnotations() {
return new AnnotationList.ForLoadedAnnotations(module.getDeclaredAnnotations());
}
@Override
public int hashCode() {
return module.hashCode();
}
@Override
public boolean equals(@MaybeNull Object other) {
if (this == other) {
return true;
} else if (!(other instanceof JavaModule)) {
return false;
}
JavaModule javaModule = (JavaModule) other;
return module.equals(javaModule.module);
}
@Override
public String toString() {
return module.toString();
}
/**
* A proxy for resolving a {@link Class}'s {@code java.lang.Module}.
*/
@JavaDispatcher.Proxied("java.lang.Class")
protected interface Resolver {
/**
* Resolves the {@code java.lang.Module} of the supplied type.
*
* @param type The type for which to resolve the module.
* @return The type's module or {@code null} if the module system is not supported.
*/
@MaybeNull
@JavaDispatcher.Defaults
Object getModule(Class type);
}
/**
* A proxy for interacting with {@code java.lang.Module}.
*/
@JavaDispatcher.Proxied("java.lang.Module")
protected interface Module {
/**
* Returns {@code true} if the supplied instance is of type {@code java.lang.Module}.
*
* @param value The instance to investigate.
* @return {@code true} if the supplied value is a {@code java.lang.Module}.
*/
@JavaDispatcher.Instance
boolean isInstance(Object value);
/**
* Returns {@code true} if the supplied module is named.
*
* @param value The {@code java.lang.Module} to check for the existence of a name.
* @return {@code true} if the supplied module is named.
*/
boolean isNamed(Object value);
/**
* Returns the module's name.
*
* @param value The {@code java.lang.Module} to check for its name.
* @return The module's (implicit or explicit) name.
*/
String getName(Object value);
/**
* Returns the class loader of a module.
*
* @param value The {@code java.lang.Module} for which to return a class loader.
* @return The module's class loader.
*/
@MaybeNull
ClassLoader getClassLoader(Object value);
/**
* Returns a resource stream for this module for a resource of the given name or {@code null} if such a resource does not exist.
*
* @param value The {@code java.lang.Module} instance to apply this method upon.
* @param name The name of the resource.
* @return An input stream for the resource or {@code null} if it does not exist.
* @throws IOException If an I/O exception occurs.
*/
@MaybeNull
InputStream getResourceAsStream(Object value, String name) throws IOException;
/**
* Returns {@code true} if the source module exports the supplied package to the target module.
*
* @param value The source module.
* @param aPackage The name of the package to check.
* @param target The target module.
* @return {@code true} if the source module exports the supplied package to the target module.
*/
boolean isExported(Object value, String aPackage, @JavaDispatcher.Proxied("java.lang.Module") Object target);
/**
* Returns {@code true} if the source module opens the supplied package to the target module.
*
* @param value The source module.
* @param aPackage The name of the package to check.
* @param target The target module.
* @return {@code true} if the source module opens the supplied package to the target module.
*/
boolean isOpen(Object value, String aPackage, @JavaDispatcher.Proxied("java.lang.Module") Object target);
/**
* Checks if the source module can read the target module.
*
* @param value The source module.
* @param target The target module.
* @return {@code true} if the source module can read the target module.
*/
boolean canRead(Object value, @JavaDispatcher.Proxied("java.lang.Module") Object target);
}
}
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