| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.commons.proxy2.impl; |
| |
| import java.lang.ref.Reference; |
| import java.lang.ref.WeakReference; |
| import java.util.Arrays; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.WeakHashMap; |
| |
| /** |
| * A cache for storing implementation classes for proxies based on a specific type of {@link ProxyClassGenerator}. A |
| * proxy class cache ensures that there is only one class for every {@link ProxyClassGenerator}/{@link ClassLoader} |
| * /proxy class array combination. |
| * |
| * @since 1.0 |
| */ |
| public class ProxyClassCache |
| { |
| |
| //****************************************************************************************************************** |
| // Fields |
| //****************************************************************************************************************** |
| |
| private final Map<ClassLoader, Map<Set<Class<?>>, WeakReference<Class<?>>>> loaderToClassCache |
| = new WeakHashMap<ClassLoader, Map<Set<Class<?>>, WeakReference<Class<?>>>>(); |
| private final ProxyClassGenerator proxyClassGenerator; |
| |
| //****************************************************************************************************************** |
| // Constructors |
| //****************************************************************************************************************** |
| |
| /** |
| * Create a new ProxyClassCache instance. |
| * |
| * @param proxyClassGenerator |
| */ |
| public ProxyClassCache(ProxyClassGenerator proxyClassGenerator) |
| { |
| this.proxyClassGenerator = proxyClassGenerator; |
| } |
| |
| //****************************************************************************************************************** |
| // Other Methods |
| //****************************************************************************************************************** |
| |
| private Map<Set<Class<?>>, WeakReference<Class<?>>> getClassCache(ClassLoader classLoader) |
| { |
| Map<Set<Class<?>>, WeakReference<Class<?>>> cache = loaderToClassCache.get(classLoader); |
| if (cache == null) |
| { |
| cache = new HashMap<Set<Class<?>>, WeakReference<Class<?>>>(); |
| loaderToClassCache.put(classLoader, cache); |
| } |
| return cache; |
| } |
| |
| private Set<Class<?>> toClassCacheKey(Class<?>[] proxyClasses) |
| { |
| return new HashSet<Class<?>>(Arrays.asList(proxyClasses)); |
| } |
| |
| /** |
| * Returns the proxy class generated by the {@link ProxyClassGenerator} using the specified {@link ClassLoader} and |
| * array of proxy classes. |
| * |
| * @param classLoader |
| * the classloader |
| * @param proxyClasses |
| * the proxy classes |
| * @return the proxy class generated by the {@link ProxyClassGenerator} using the specified {@link ClassLoader} and |
| * array of proxy classes |
| */ |
| public synchronized Class<?> getProxyClass(ClassLoader classLoader, Class<?>[] proxyClasses) |
| { |
| final Map<Set<Class<?>>, WeakReference<Class<?>>> classCache = getClassCache(classLoader); |
| final Set<Class<?>> key = toClassCacheKey(proxyClasses); |
| Class<?> proxyClass; |
| Reference<Class<?>> proxyClassReference = classCache.get(key); |
| if (proxyClassReference == null) |
| { |
| proxyClass = proxyClassGenerator.generateProxyClass(classLoader, proxyClasses); |
| classCache.put(key, new WeakReference<Class<?>>(proxyClass)); |
| } |
| else |
| { |
| synchronized (proxyClassReference) |
| { |
| proxyClass = proxyClassReference.get(); |
| if (proxyClass == null) |
| { |
| proxyClass = proxyClassGenerator.generateProxyClass(classLoader, proxyClasses); |
| classCache.put(key, new WeakReference<Class<?>>(proxyClass)); |
| } |
| } |
| } |
| return proxyClass; |
| } |
| } |