org.powermock.classloading.ClassloaderExecutor Maven / Gradle / Ivy
/*
* Copyright 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.powermock.classloading;
import org.powermock.classloading.spi.DeepClonerSPI;
import java.util.concurrent.Callable;
/**
* A ClassLoaderExecutor can run any code in any classloader. E.g. assume you have a classloader
* called myClassloader and you want to execute a (void) method called myMethod in myObject using this CL:
*
* SingleClassloaderExecutor cle = new SingleClassloaderExecutor(myClassloader);
* cle.execute(new Runnable() {
* public void run() {
* myObject.myMethod();
* }
* });
*
*
* What happens is that the entire object graph of myObject is deep-cloned into the {@code myClassloader} classloader
* and then the {@code myObject.myMethod()} is executed.
*
* You can also execute methods that return something:
*
* SingleClassloaderExecutor cle = new SingleClassloaderExecutor(myClassloader);
* MyResult result = cle.execute(new Callable() {
* public MyResult call() throws Exception {
* return myObject.myMethod();
* }
* });
*
* Here we imagine that {@code myObject.myMethod()} returns an object of type {@code MyResult}. Again the entire
* state will be deep-cloned to {@code myClassloader} and then the {@code myObject.myMethod()} is executed.
* The result of the method call is deep-cloned back into the original classloader (the one that made the call to
* {@code cle.execute(..)}) and is ready for use.
*
*
* Note that the SingleClassloaderExecutor requires a deep cloner implementing the {@link DeepClonerSPI} present in the class-path.
*
*/
public interface ClassloaderExecutor {
T execute(Callable callable);
void execute(Runnable runnable);
}