001/* 002 * Copyright 2002-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.context.weaving; 018 019import java.lang.instrument.ClassFileTransformer; 020import java.lang.instrument.IllegalClassFormatException; 021import java.security.ProtectionDomain; 022 023import org.aspectj.weaver.loadtime.ClassPreProcessorAgentAdapter; 024 025import org.springframework.beans.BeansException; 026import org.springframework.beans.factory.BeanClassLoaderAware; 027import org.springframework.beans.factory.config.BeanFactoryPostProcessor; 028import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; 029import org.springframework.core.Ordered; 030import org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver; 031import org.springframework.instrument.classloading.LoadTimeWeaver; 032import org.springframework.lang.Nullable; 033 034/** 035 * Post-processor that registers AspectJ's 036 * {@link org.aspectj.weaver.loadtime.ClassPreProcessorAgentAdapter} 037 * with the Spring application context's default 038 * {@link org.springframework.instrument.classloading.LoadTimeWeaver}. 039 * 040 * @author Juergen Hoeller 041 * @author Ramnivas Laddad 042 * @since 2.5 043 */ 044public class AspectJWeavingEnabler 045 implements BeanFactoryPostProcessor, BeanClassLoaderAware, LoadTimeWeaverAware, Ordered { 046 047 /** 048 * The {@code aop.xml} resource location. 049 */ 050 public static final String ASPECTJ_AOP_XML_RESOURCE = "META-INF/aop.xml"; 051 052 053 @Nullable 054 private ClassLoader beanClassLoader; 055 056 @Nullable 057 private LoadTimeWeaver loadTimeWeaver; 058 059 060 @Override 061 public void setBeanClassLoader(ClassLoader classLoader) { 062 this.beanClassLoader = classLoader; 063 } 064 065 @Override 066 public void setLoadTimeWeaver(LoadTimeWeaver loadTimeWeaver) { 067 this.loadTimeWeaver = loadTimeWeaver; 068 } 069 070 @Override 071 public int getOrder() { 072 return HIGHEST_PRECEDENCE; 073 } 074 075 @Override 076 public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException { 077 enableAspectJWeaving(this.loadTimeWeaver, this.beanClassLoader); 078 } 079 080 081 /** 082 * Enable AspectJ weaving with the given {@link LoadTimeWeaver}. 083 * @param weaverToUse the LoadTimeWeaver to apply to (or {@code null} for a default weaver) 084 * @param beanClassLoader the class loader to create a default weaver for (if necessary) 085 */ 086 public static void enableAspectJWeaving( 087 @Nullable LoadTimeWeaver weaverToUse, @Nullable ClassLoader beanClassLoader) { 088 089 if (weaverToUse == null) { 090 if (InstrumentationLoadTimeWeaver.isInstrumentationAvailable()) { 091 weaverToUse = new InstrumentationLoadTimeWeaver(beanClassLoader); 092 } 093 else { 094 throw new IllegalStateException("No LoadTimeWeaver available"); 095 } 096 } 097 weaverToUse.addTransformer( 098 new AspectJClassBypassingClassFileTransformer(new ClassPreProcessorAgentAdapter())); 099 } 100 101 102 /** 103 * ClassFileTransformer decorator that suppresses processing of AspectJ 104 * classes in order to avoid potential LinkageErrors. 105 * @see org.springframework.context.annotation.LoadTimeWeavingConfiguration 106 */ 107 private static class AspectJClassBypassingClassFileTransformer implements ClassFileTransformer { 108 109 private final ClassFileTransformer delegate; 110 111 public AspectJClassBypassingClassFileTransformer(ClassFileTransformer delegate) { 112 this.delegate = delegate; 113 } 114 115 @Override 116 public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, 117 ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { 118 119 if (className.startsWith("org.aspectj") || className.startsWith("org/aspectj")) { 120 return classfileBuffer; 121 } 122 return this.delegate.transform(loader, className, classBeingRedefined, protectionDomain, classfileBuffer); 123 } 124 } 125 126}