org.springframework.instrument.classloading.websphere.WebSphereClassLoaderAdapter Maven / Gradle / Ivy
/*
* Copyright 2002-2016 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.instrument.classloading.websphere;
import java.lang.instrument.ClassFileTransformer;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.List;
import org.springframework.util.Assert;
/**
*
* Reflective wrapper around a WebSphere 7+ class loader. Used to
* encapsulate the classloader-specific methods (discovered and
* called through reflection) from the load-time weaver.
*
* @author Costin Leau
* @author Juergen Hoeller
* @since 3.1
*/
class WebSphereClassLoaderAdapter {
private static final String COMPOUND_CLASS_LOADER_NAME = "com.ibm.ws.classloader.CompoundClassLoader";
private static final String CLASS_PRE_PROCESSOR_NAME = "com.ibm.websphere.classloader.ClassLoaderInstancePreDefinePlugin";
private static final String PLUGINS_FIELD = "preDefinePlugins";
private ClassLoader classLoader;
private Class wsPreProcessorClass;
private Method addPreDefinePlugin;
private Constructor cloneConstructor;
private Field transformerList;
public WebSphereClassLoaderAdapter(ClassLoader classLoader) {
Class wsCompoundClassLoaderClass;
try {
wsCompoundClassLoaderClass = classLoader.loadClass(COMPOUND_CLASS_LOADER_NAME);
this.cloneConstructor = classLoader.getClass().getDeclaredConstructor(wsCompoundClassLoaderClass);
this.cloneConstructor.setAccessible(true);
this.wsPreProcessorClass = classLoader.loadClass(CLASS_PRE_PROCESSOR_NAME);
this.addPreDefinePlugin = classLoader.getClass().getMethod("addPreDefinePlugin", this.wsPreProcessorClass);
this.transformerList = wsCompoundClassLoaderClass.getDeclaredField(PLUGINS_FIELD);
this.transformerList.setAccessible(true);
}
catch (Exception ex) {
throw new IllegalStateException(
"Could not initialize WebSphere LoadTimeWeaver because WebSphere API classes are not available", ex);
}
if (!wsCompoundClassLoaderClass.isInstance(classLoader)) {
throw new IllegalArgumentException("ClassLoader must be instance of [" + COMPOUND_CLASS_LOADER_NAME + "]");
}
this.classLoader = classLoader;
}
public ClassLoader getClassLoader() {
return this.classLoader;
}
public void addTransformer(ClassFileTransformer transformer) {
Assert.notNull(transformer, "ClassFileTransformer must not be null");
try {
InvocationHandler adapter = new WebSphereClassPreDefinePlugin(transformer);
Object adapterInstance = Proxy.newProxyInstance(this.wsPreProcessorClass.getClassLoader(),
new Class[] {this.wsPreProcessorClass}, adapter);
this.addPreDefinePlugin.invoke(this.classLoader, adapterInstance);
}
catch (InvocationTargetException ex) {
throw new IllegalStateException("WebSphere addPreDefinePlugin method threw exception", ex.getCause());
}
catch (Exception ex) {
throw new IllegalStateException("Could not invoke WebSphere addPreDefinePlugin method", ex);
}
}
public ClassLoader getThrowawayClassLoader() {
try {
ClassLoader loader = this.cloneConstructor.newInstance(getClassLoader());
// Clear out the transformers (copied as well)
List list = (List) this.transformerList.get(loader);
list.clear();
return loader;
}
catch (InvocationTargetException ex) {
throw new IllegalStateException("WebSphere CompoundClassLoader constructor failed", ex.getCause());
}
catch (Exception ex) {
throw new IllegalStateException("Could not construct WebSphere CompoundClassLoader", ex);
}
}
}