jdk8-mips64-public/nashorn: comparison src/jdk/internal/dynalink/support/ClassMap.java

-:43e32b36153c
+:5a820fb11814
+/*
+* 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.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.
+*
+* @author Attila Szegedi
+* @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(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 class loader that governs the strong referenceability of this class map.
+*
+* @return the class loader that governs the strong referenceability of this class map.
+*/
+public ClassLoader getClassLoader() {
+return classLoader;
+}
+/**
+* Returns the value associated with the class
+*
+* @param clazz the class
+* @return the value associated with the class
+*/
+public T get(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;
+// If allowed to strongly reference, put it in the fast map
+if(Guards.canReferenceDirectly(classLoader, clazz.getClassLoader())) {
+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;
+}
+}
+}

Mercurial > jdk8-mips64-public > nashorn / file comparison

comparison: src/jdk/internal/dynalink/support/ClassMap.java

src/jdk/internal/dynalink/support/ClassMap.java