org.springframework.context.weaving.DefaultContextLoadTimeWeaver Maven / Gradle / Ivy
/*
* Copyright 2002-2023 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
*
* https://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 org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.instrument.InstrumentationSavingAgent;
import org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver;
import org.springframework.instrument.classloading.LoadTimeWeaver;
import org.springframework.instrument.classloading.ReflectiveLoadTimeWeaver;
import org.springframework.instrument.classloading.glassfish.GlassFishLoadTimeWeaver;
import org.springframework.instrument.classloading.jboss.JBossLoadTimeWeaver;
import org.springframework.instrument.classloading.tomcat.TomcatLoadTimeWeaver;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* Default {@link LoadTimeWeaver} bean for use in an application context,
* decorating an automatically detected internal {@code LoadTimeWeaver}.
*
* Typically registered for the default bean name "{@code loadTimeWeaver}";
* the most convenient way to achieve this is Spring's
* {@code } XML tag or {@code @EnableLoadTimeWeaving}
* on a {@code @Configuration} class.
*
* This class implements a runtime environment check for obtaining the
* appropriate weaver implementation, including
* {@link InstrumentationSavingAgent Spring's VM agent} and any {@link ClassLoader}
* supported by Spring's {@link ReflectiveLoadTimeWeaver}.
*
* @author Juergen Hoeller
* @author Ramnivas Laddad
* @author Costin Leau
* @since 2.5
* @see org.springframework.context.ConfigurableApplicationContext#LOAD_TIME_WEAVER_BEAN_NAME
*/
public class DefaultContextLoadTimeWeaver implements LoadTimeWeaver, BeanClassLoaderAware, DisposableBean {
protected final Log logger = LogFactory.getLog(getClass());
@Nullable
private LoadTimeWeaver loadTimeWeaver;
public DefaultContextLoadTimeWeaver() {
}
public DefaultContextLoadTimeWeaver(ClassLoader beanClassLoader) {
setBeanClassLoader(beanClassLoader);
}
@Override
public void setBeanClassLoader(ClassLoader classLoader) {
LoadTimeWeaver serverSpecificLoadTimeWeaver = createServerSpecificLoadTimeWeaver(classLoader);
if (serverSpecificLoadTimeWeaver != null) {
if (logger.isDebugEnabled()) {
logger.debug("Determined server-specific load-time weaver: " +
serverSpecificLoadTimeWeaver.getClass().getName());
}
this.loadTimeWeaver = serverSpecificLoadTimeWeaver;
}
else if (InstrumentationLoadTimeWeaver.isInstrumentationAvailable()) {
logger.debug("Found Spring's JVM agent for instrumentation");
this.loadTimeWeaver = new InstrumentationLoadTimeWeaver(classLoader);
}
else {
try {
this.loadTimeWeaver = new ReflectiveLoadTimeWeaver(classLoader);
if (logger.isDebugEnabled()) {
logger.debug("Using reflective load-time weaver for class loader: " +
this.loadTimeWeaver.getInstrumentableClassLoader().getClass().getName());
}
}
catch (IllegalStateException ex) {
throw new IllegalStateException(ex.getMessage() + " Specify a custom LoadTimeWeaver or start your " +
"Java virtual machine with Spring's agent: -javaagent:spring-instrument-{version}.jar");
}
}
}
/*
* This method never fails, allowing to try other possible ways to use a
* server-agnostic weaver. This non-failure logic is required since
* determining a load-time weaver based on the ClassLoader name alone may
* legitimately fail due to other mismatches.
*/
@Nullable
protected LoadTimeWeaver createServerSpecificLoadTimeWeaver(ClassLoader classLoader) {
String name = classLoader.getClass().getName();
try {
if (name.startsWith("org.apache.catalina")) {
return new TomcatLoadTimeWeaver(classLoader);
}
else if (name.startsWith("org.glassfish")) {
return new GlassFishLoadTimeWeaver(classLoader);
}
else if (name.startsWith("org.jboss.modules")) {
return new JBossLoadTimeWeaver(classLoader);
}
}
catch (Exception ex) {
if (logger.isInfoEnabled()) {
logger.info("Could not obtain server-specific LoadTimeWeaver: " + ex.getMessage());
}
}
return null;
}
@Override
public void destroy() {
if (this.loadTimeWeaver instanceof InstrumentationLoadTimeWeaver iltw) {
if (logger.isDebugEnabled()) {
logger.debug("Removing all registered transformers for class loader: " +
this.loadTimeWeaver.getInstrumentableClassLoader().getClass().getName());
}
iltw.removeTransformers();
}
}
@Override
public void addTransformer(ClassFileTransformer transformer) {
Assert.state(this.loadTimeWeaver != null, "Not initialized");
this.loadTimeWeaver.addTransformer(transformer);
}
@Override
public ClassLoader getInstrumentableClassLoader() {
Assert.state(this.loadTimeWeaver != null, "Not initialized");
return this.loadTimeWeaver.getInstrumentableClassLoader();
}
@Override
public ClassLoader getThrowawayClassLoader() {
Assert.state(this.loadTimeWeaver != null, "Not initialized");
return this.loadTimeWeaver.getThrowawayClassLoader();
}
}