| /* |
| * Copyright (c) 2010, 2013, 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. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file, and Oracle licenses the original version of this file under the BSD |
| * license: |
| */ |
| /* |
| Copyright 2009-2013 Attila Szegedi |
| |
| Licensed under both the Apache License, Version 2.0 (the "Apache License") |
| and the BSD License (the "BSD License"), with licensee being free to |
| choose either of the two at their discretion. |
| |
| You may not use this file except in compliance with either the Apache |
| License or the BSD License. |
| |
| If you choose to use this file in compliance with the Apache License, the |
| following notice applies to you: |
| |
| You may obtain a copy of the Apache 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. |
| |
| If you choose to use this file in compliance with the BSD License, the |
| following notice applies to you: |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| * Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| * Neither the name of the copyright holder nor the names of |
| contributors may be used to endorse or promote products derived from |
| this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
| IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
| PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER |
| BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
| BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package jdk.internal.dynalink.support; |
| |
| import java.lang.ref.Reference; |
| import java.lang.ref.SoftReference; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.Map; |
| import java.util.WeakHashMap; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| |
| /** |
| * A dual map that can either strongly or weakly reference a given class depending on whether the class is visible from |
| * a class loader or not. |
| * |
| * @param <T> the type of the values in the map |
| */ |
| public abstract class ClassMap<T> { |
| private final ConcurrentMap<Class<?>, T> map = new ConcurrentHashMap<>(); |
| private final Map<Class<?>, Reference<T>> weakMap = new WeakHashMap<>(); |
| private final ClassLoader classLoader; |
| |
| /** |
| * Creates a new class map. It will use strong references for all keys and values where the key is a class visible |
| * from the class loader, and will use weak keys and soft values for all other classes. |
| * |
| * @param classLoader the classloader that determines strong referenceability. |
| */ |
| protected ClassMap(final ClassLoader classLoader) { |
| this.classLoader = classLoader; |
| } |
| |
| /** |
| * Compute the value associated with the given class. It is possible that the method will be invoked several times |
| * (or even concurrently) for the same class parameter. |
| * |
| * @param clazz the class to compute the value for |
| * @return the return value. Must not be null. |
| */ |
| protected abstract T computeValue(Class<?> clazz); |
| |
| /** |
| * Returns the value associated with the class |
| * |
| * @param clazz the class |
| * @return the value associated with the class |
| */ |
| public T get(final Class<?> clazz) { |
| // Check in fastest first - objects we're allowed to strongly reference |
| final T v = map.get(clazz); |
| if(v != null) { |
| return v; |
| } |
| // Check objects we're not allowed to strongly reference |
| Reference<T> ref; |
| synchronized(weakMap) { |
| ref = weakMap.get(clazz); |
| } |
| if(ref != null) { |
| final T refv = ref.get(); |
| if(refv != null) { |
| return refv; |
| } |
| } |
| // Not found in either place; create a new value |
| final T newV = computeValue(clazz); |
| assert newV != null; |
| |
| final ClassLoader clazzLoader = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() { |
| @Override |
| public ClassLoader run() { |
| return clazz.getClassLoader(); |
| } |
| }, ClassLoaderGetterContextProvider.GET_CLASS_LOADER_CONTEXT); |
| |
| // If allowed to strongly reference, put it in the fast map |
| if(Guards.canReferenceDirectly(classLoader, clazzLoader)) { |
| final T oldV = map.putIfAbsent(clazz, newV); |
| return oldV != null ? oldV : newV; |
| } |
| // Otherwise, put it into the weak map |
| synchronized(weakMap) { |
| ref = weakMap.get(clazz); |
| if(ref != null) { |
| final T oldV = ref.get(); |
| if(oldV != null) { |
| return oldV; |
| } |
| } |
| weakMap.put(clazz, new SoftReference<>(newV)); |
| return newV; |
| } |
| } |
| } |