Spring Framework example source code file (AspectJWeavingEnabler.java)

This example Spring Framework source code file (AspectJWeavingEnabler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

aspectjclassbypassingclassfiletransformer, aspectjclassbypassingclassfiletransformer, beanclassloaderaware, beanfactorypostprocessor, classfiletransformer, classfiletransformer, classloader, classpreprocessoragentadapter, illegalclassformatexception, loadtimeweaver, loadtimeweaver, loadtimeweaveraware, ordered, security, string

The Spring Framework AspectJWeavingEnabler.java source code

/*
 * Copyright 2002-2008 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.
 */

package org.springframework.context.weaving;

import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;

import org.aspectj.weaver.loadtime.ClassPreProcessorAgentAdapter;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.core.Ordered;
import org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver;
import org.springframework.instrument.classloading.LoadTimeWeaver;

/**
 * Post-processor that registers AspectJ's
 * {@link org.aspectj.weaver.loadtime.ClassPreProcessorAgentAdapter}
 * with the Spring application context's default
 * {@link org.springframework.instrument.classloading.LoadTimeWeaver}.
 *
 * @author Juergen Hoeller
 * @author Ramnivas Laddad
 * @since 2.5
 */
public class AspectJWeavingEnabler
		implements BeanFactoryPostProcessor, BeanClassLoaderAware, LoadTimeWeaverAware, Ordered {

	private ClassLoader beanClassLoader;

	private LoadTimeWeaver loadTimeWeaver;


	public void setBeanClassLoader(ClassLoader classLoader) {
		this.beanClassLoader = classLoader;
	}

	public void setLoadTimeWeaver(LoadTimeWeaver loadTimeWeaver) {
		this.loadTimeWeaver = loadTimeWeaver;
	}

	public int getOrder() {
		return HIGHEST_PRECEDENCE;
	}


	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
		LoadTimeWeaver weaverToUse = this.loadTimeWeaver;
		if (weaverToUse == null && InstrumentationLoadTimeWeaver.isInstrumentationAvailable()) {
			weaverToUse = new InstrumentationLoadTimeWeaver(this.beanClassLoader);
		}
		weaverToUse.addTransformer(new AspectJClassBypassingClassFileTransformer(
					new ClassPreProcessorAgentAdapter()));
	}


	/*
	 * Decorator to suppress processing AspectJ classes, hence avoiding potential LinkageErrors.
	 * OC4J and Tomcat (in Glassfish) definitely need such bypassing of AspectJ classes.
	 */
	private static class AspectJClassBypassingClassFileTransformer implements ClassFileTransformer {

		private final ClassFileTransformer delegate;
		
		public AspectJClassBypassingClassFileTransformer(ClassFileTransformer delegate) {
			this.delegate = delegate;
		}
		
		public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
				ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {

			if (className.startsWith("org.aspectj") || className.startsWith("org/aspectj")) {
				return classfileBuffer;
			}
			return this.delegate.transform(loader, className, classBeingRedefined, protectionDomain, classfileBuffer);
		}
	}

}