/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed 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.
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package org.springframework.context.annotation;

import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.EnableLoadTimeWeaving.AspectJWeaving;
import org.springframework.context.weaving.AspectJWeavingEnabler;
import org.springframework.context.weaving.DefaultContextLoadTimeWeaver;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.instrument.classloading.LoadTimeWeaver;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

@Configuration class that registers a LoadTimeWeaver bean.

This configuration class is automatically imported when using the EnableLoadTimeWeaving annotation. See @EnableLoadTimeWeaving javadoc for complete usage details.

Author:Chris Beams
See Also:
Since:3.1
/** * {@code @Configuration} class that registers a {@link LoadTimeWeaver} bean. * * <p>This configuration class is automatically imported when using the * {@link EnableLoadTimeWeaving} annotation. See {@code @EnableLoadTimeWeaving} * javadoc for complete usage details. * * @author Chris Beams * @since 3.1 * @see LoadTimeWeavingConfigurer * @see ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME */
@Configuration public class LoadTimeWeavingConfiguration implements ImportAware, BeanClassLoaderAware { @Nullable private AnnotationAttributes enableLTW; @Nullable private LoadTimeWeavingConfigurer ltwConfigurer; @Nullable private ClassLoader beanClassLoader; @Override public void setImportMetadata(AnnotationMetadata importMetadata) { this.enableLTW = AnnotationConfigUtils.attributesFor(importMetadata, EnableLoadTimeWeaving.class); if (this.enableLTW == null) { throw new IllegalArgumentException( "@EnableLoadTimeWeaving is not present on importing class " + importMetadata.getClassName()); } } @Autowired(required = false) public void setLoadTimeWeavingConfigurer(LoadTimeWeavingConfigurer ltwConfigurer) { this.ltwConfigurer = ltwConfigurer; } @Override public void setBeanClassLoader(ClassLoader beanClassLoader) { this.beanClassLoader = beanClassLoader; } @Bean(name = ConfigurableApplicationContext.LOAD_TIME_WEAVER_BEAN_NAME) @Role(BeanDefinition.ROLE_INFRASTRUCTURE) public LoadTimeWeaver loadTimeWeaver() { Assert.state(this.beanClassLoader != null, "No ClassLoader set"); LoadTimeWeaver loadTimeWeaver = null; if (this.ltwConfigurer != null) { // The user has provided a custom LoadTimeWeaver instance loadTimeWeaver = this.ltwConfigurer.getLoadTimeWeaver(); } if (loadTimeWeaver == null) { // No custom LoadTimeWeaver provided -> fall back to the default loadTimeWeaver = new DefaultContextLoadTimeWeaver(this.beanClassLoader); } if (this.enableLTW != null) { AspectJWeaving aspectJWeaving = this.enableLTW.getEnum("aspectjWeaving"); switch (aspectJWeaving) { case DISABLED: // AJ weaving is disabled -> do nothing break; case AUTODETECT: if (this.beanClassLoader.getResource(AspectJWeavingEnabler.ASPECTJ_AOP_XML_RESOURCE) == null) { // No aop.xml present on the classpath -> treat as 'disabled' break; } // aop.xml is present on the classpath -> enable AspectJWeavingEnabler.enableAspectJWeaving(loadTimeWeaver, this.beanClassLoader); break; case ENABLED: AspectJWeavingEnabler.enableAspectJWeaving(loadTimeWeaver, this.beanClassLoader); break; } } return loadTimeWeaver; } }