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.util.Assert; 022import org.springframework.util.ClassUtils; 023 024/** 025 * {@code LoadTimeWeaver} that builds and exposes a 026 * {@link SimpleInstrumentableClassLoader}. 027 * 028 * <p>Mainly intended for testing environments, where it is sufficient to 029 * perform all class transformation on a newly created 030 * {@code ClassLoader} instance. 031 * 032 * @author Rod Johnson 033 * @author Juergen Hoeller 034 * @since 2.0 035 * @see #getInstrumentableClassLoader() 036 * @see SimpleInstrumentableClassLoader 037 * @see ReflectiveLoadTimeWeaver 038 */ 039public class SimpleLoadTimeWeaver implements LoadTimeWeaver { 040 041 private final SimpleInstrumentableClassLoader classLoader; 042 043 044 /** 045 * Create a new {@code SimpleLoadTimeWeaver} for the current context 046 * {@code ClassLoader}. 047 * @see SimpleInstrumentableClassLoader 048 */ 049 public SimpleLoadTimeWeaver() { 050 this.classLoader = new SimpleInstrumentableClassLoader(ClassUtils.getDefaultClassLoader()); 051 } 052 053 /** 054 * Create a new {@code SimpleLoadTimeWeaver} for the given 055 * {@code ClassLoader}. 056 * @param classLoader the {@code ClassLoader} to build a simple 057 * instrumentable {@code ClassLoader} on top of 058 */ 059 public SimpleLoadTimeWeaver(SimpleInstrumentableClassLoader classLoader) { 060 Assert.notNull(classLoader, "ClassLoader must not be null"); 061 this.classLoader = classLoader; 062 } 063 064 065 @Override 066 public void addTransformer(ClassFileTransformer transformer) { 067 this.classLoader.addTransformer(transformer); 068 } 069 070 @Override 071 public ClassLoader getInstrumentableClassLoader() { 072 return this.classLoader; 073 } 074 075 /** 076 * This implementation builds a {@link SimpleThrowawayClassLoader}. 077 */ 078 @Override 079 public ClassLoader getThrowawayClassLoader() { 080 return new SimpleThrowawayClassLoader(getInstrumentableClassLoader()); 081 } 082 083}