001/*
002 * Copyright 2002-2019 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.jboss;
018
019import java.lang.instrument.ClassFileTransformer;
020import java.lang.reflect.Field;
021import java.lang.reflect.Method;
022
023import org.springframework.instrument.classloading.LoadTimeWeaver;
024import org.springframework.instrument.classloading.SimpleThrowawayClassLoader;
025import org.springframework.lang.Nullable;
026import org.springframework.util.Assert;
027import org.springframework.util.ClassUtils;
028import org.springframework.util.ReflectionUtils;
029
030/**
031 * {@link LoadTimeWeaver} implementation for JBoss's instrumentable ClassLoader.
032 * Thanks to Ales Justin and Marius Bogoevici for the initial prototype.
033 *
034 * <p>As of Spring Framework 5.0, this weaver supports WildFly 8+.
035 * As of Spring Framework 5.1.5, it also supports WildFly 13+.
036 *
037 * @author Costin Leau
038 * @author Juergen Hoeller
039 * @since 3.0
040 */
041public class JBossLoadTimeWeaver implements LoadTimeWeaver {
042
043        private static final String DELEGATING_TRANSFORMER_CLASS_NAME =
044                        "org.jboss.as.server.deployment.module.DelegatingClassFileTransformer";
045
046        private static final String WRAPPER_TRANSFORMER_CLASS_NAME =
047                        "org.jboss.modules.JLIClassTransformer";
048
049
050        private final ClassLoader classLoader;
051
052        private final Object delegatingTransformer;
053
054        private final Method addTransformer;
055
056
057        /**
058         * Create a new instance of the {@link JBossLoadTimeWeaver} class using
059         * the default {@link ClassLoader class loader}.
060         * @see org.springframework.util.ClassUtils#getDefaultClassLoader()
061         */
062        public JBossLoadTimeWeaver() {
063                this(ClassUtils.getDefaultClassLoader());
064        }
065
066        /**
067         * Create a new instance of the {@link JBossLoadTimeWeaver} class using
068         * the supplied {@link ClassLoader}.
069         * @param classLoader the {@code ClassLoader} to delegate to for weaving
070         */
071        public JBossLoadTimeWeaver(@Nullable ClassLoader classLoader) {
072                Assert.notNull(classLoader, "ClassLoader must not be null");
073                this.classLoader = classLoader;
074
075                try {
076                        Field transformer = ReflectionUtils.findField(classLoader.getClass(), "transformer");
077                        if (transformer == null) {
078                                throw new IllegalArgumentException("Could not find 'transformer' field on JBoss ClassLoader: " +
079                                                classLoader.getClass().getName());
080                        }
081                        transformer.setAccessible(true);
082
083                        Object suggestedTransformer = transformer.get(classLoader);
084                        if (suggestedTransformer.getClass().getName().equals(WRAPPER_TRANSFORMER_CLASS_NAME)) {
085                                Field wrappedTransformer = ReflectionUtils.findField(suggestedTransformer.getClass(), "transformer");
086                                if (wrappedTransformer == null) {
087                                        throw new IllegalArgumentException(
088                                                        "Could not find 'transformer' field on JBoss JLIClassTransformer: " +
089                                                        suggestedTransformer.getClass().getName());
090                                }
091                                wrappedTransformer.setAccessible(true);
092                                suggestedTransformer = wrappedTransformer.get(suggestedTransformer);
093                        }
094                        if (!suggestedTransformer.getClass().getName().equals(DELEGATING_TRANSFORMER_CLASS_NAME)) {
095                                throw new IllegalStateException(
096                                                "Transformer not of the expected type DelegatingClassFileTransformer: " +
097                                                suggestedTransformer.getClass().getName());
098                        }
099                        this.delegatingTransformer = suggestedTransformer;
100
101                        Method addTransformer = ReflectionUtils.findMethod(this.delegatingTransformer.getClass(),
102                                        "addTransformer", ClassFileTransformer.class);
103                        if (addTransformer == null) {
104                                throw new IllegalArgumentException(
105                                                "Could not find 'addTransformer' method on JBoss DelegatingClassFileTransformer: " +
106                                                this.delegatingTransformer.getClass().getName());
107                        }
108                        addTransformer.setAccessible(true);
109                        this.addTransformer = addTransformer;
110                }
111                catch (Throwable ex) {
112                        throw new IllegalStateException("Could not initialize JBoss LoadTimeWeaver", ex);
113                }
114        }
115
116
117        @Override
118        public void addTransformer(ClassFileTransformer transformer) {
119                try {
120                        this.addTransformer.invoke(this.delegatingTransformer, transformer);
121                }
122                catch (Throwable ex) {
123                        throw new IllegalStateException("Could not add transformer on JBoss ClassLoader: " + this.classLoader, ex);
124                }
125        }
126
127        @Override
128        public ClassLoader getInstrumentableClassLoader() {
129                return this.classLoader;
130        }
131
132        @Override
133        public ClassLoader getThrowawayClassLoader() {
134                return new SimpleThrowawayClassLoader(getInstrumentableClassLoader());
135        }
136
137}