| /* |
| * Copyright (c) 2014, 2020 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // Contributors: |
| // Marcel Valovy - 2.6 - initial API and implementation |
| package org.eclipse.persistence.testing.perf.reflection; |
| |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.ThreadMXBean; |
| import java.lang.ref.SoftReference; |
| import java.lang.reflect.Field; |
| import java.lang.reflect.Method; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.ArrayList; |
| import java.util.Deque; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.concurrent.ConcurrentLinkedDeque; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| /** |
| * INTERNAL: |
| * |
| * Utility class for bean validation related tasks. |
| * - Singleton. |
| * - Thread-safe. |
| */ |
| public class SimpleConcurrentReflectionUtils { |
| |
| /** |
| * Retrieves declared fields. |
| * <p/> |
| * If security is enabled, makes {@linkplain java.security.AccessController#doPrivileged(java.security.PrivilegedAction) |
| * privileged calls}. |
| * |
| * @param clazz fields of that class will be returned |
| * @return array of declared fields |
| * @see Class#getDeclaredFields() |
| */ |
| static Field[] getDeclaredFields(Class<?> clazz) { |
| return PrivilegedAccessHelper.shouldUsePrivilegedAccess() |
| ? AccessController.doPrivileged(PREDICATE_ACTION.with(clazz)) |
| : getDeclaredFieldsInternal(clazz); |
| } |
| |
| /** |
| * Enhanced {@link PrivilegedAction} using predicates. |
| * - Singleton. |
| */ |
| private static final Predicate<Field[]> PREDICATE_ACTION = new |
| Predicate<Field[]>() { |
| |
| /* Predicates */ |
| private Class<?> clazz; |
| |
| /** |
| * Lock that allows for concurrent usage of this instance. |
| */ |
| private final ReentrantLock lock = new ReentrantLock(); |
| |
| @Override |
| public Field[] run() { |
| // We are still inside memory barrier, thus it is guaranteed that value of #clazz was assigned by |
| // current thread. |
| Class<?> localReference = clazz; |
| // Leaving memory barrier before executing cpu extensive operation. |
| lock.unlock(); |
| // Possibly we should clear clazz reference here, since the instances are pooled. However, |
| // the field should always be reassigned before running run() method and even if someone |
| // intentionally did not, it poses no security threat. |
| // Computation on value that is guaranteed to have been assigned by current thread. |
| return getDeclaredFieldsInternal(localReference); |
| } |
| |
| @Override |
| public Predicate<Field[]> with(Class<?> clazz) { |
| lock.lock(); |
| this.clazz = clazz; |
| return this; |
| } |
| }; |
| |
| /** |
| * INTERNAL: |
| */ |
| private static Field[] getDeclaredFieldsInternal(Class<?> clazz) { |
| return clazz.getDeclaredFields(); |
| } |
| |
| /** |
| * Predicate-providing wrapper for {@link PrivilegedAction}. |
| * |
| * @param <T> return type of {@linkplain PrivilegedAction#run() computation} |
| */ |
| private interface Predicate<T> extends PrivilegedAction<T> { |
| |
| /** |
| * Assigns a predicate to the underlying privileged action. |
| * Any previous predicate of the same type will be overwritten. |
| * |
| * @param with predicate |
| * @return {@code this} |
| */ |
| Predicate<T> with(Class<?> with); |
| } |
| |
| } |