001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.instrument.classloading;
018
019import java.lang.instrument.ClassFileTransformer;
020
021import org.springframework.core.OverridingClassLoader;
022import org.springframework.lang.Nullable;
023
024/**
025 * Simplistic implementation of an instrumentable {@code ClassLoader}.
026 *
027 * <p>Usable in tests and standalone environments.
028 *
029 * @author Rod Johnson
030 * @author Costin Leau
031 * @since 2.0
032 */
033public class SimpleInstrumentableClassLoader extends OverridingClassLoader {
034
035        static {
036                ClassLoader.registerAsParallelCapable();
037        }
038
039
040        private final WeavingTransformer weavingTransformer;
041
042
043        /**
044         * Create a new SimpleInstrumentableClassLoader for the given ClassLoader.
045         * @param parent the ClassLoader to build an instrumentable ClassLoader for
046         */
047        public SimpleInstrumentableClassLoader(@Nullable ClassLoader parent) {
048                super(parent);
049                this.weavingTransformer = new WeavingTransformer(parent);
050        }
051
052
053        /**
054         * Add a {@link ClassFileTransformer} to be applied by this ClassLoader.
055         * @param transformer the {@link ClassFileTransformer} to register
056         */
057        public void addTransformer(ClassFileTransformer transformer) {
058                this.weavingTransformer.addTransformer(transformer);
059        }
060
061
062        @Override
063        protected byte[] transformIfNecessary(String name, byte[] bytes) {
064                return this.weavingTransformer.transformIfNecessary(name, bytes);
065        }
066
067}