| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.tomcat; |
| |
| import java.lang.instrument.ClassFileTransformer; |
| |
| /** |
| * Specifies a class loader capable of being decorated with |
| * {@link ClassFileTransformer}s. These transformers can instrument |
| * (or weave) the byte code of classes loaded through this class loader |
| * to alter their behavior. Currently only |
| * {@link org.apache.catalina.loader.WebappClassLoaderBase} implements this |
| * interface. This allows web application frameworks or JPA providers |
| * bundled with a web application to instrument web application classes |
| * as necessary. |
| * <p> |
| * You should always program against the methods of this interface |
| * (whether using reflection or otherwise). The methods in |
| * {@code WebappClassLoaderBase} are protected by the default security |
| * manager if one is in use. |
| * |
| * @since 8.0, 7.0.64 |
| */ |
| public interface InstrumentableClassLoader { |
| |
| /** |
| * Adds the specified class file transformer to this class loader. The |
| * transformer will then be able to instrument the bytecode of any |
| * classes loaded by this class loader after the invocation of this |
| * method. |
| * |
| * @param transformer The transformer to add to the class loader |
| * @throws IllegalArgumentException if the {@literal transformer} is null. |
| */ |
| void addTransformer(ClassFileTransformer transformer); |
| |
| /** |
| * Removes the specified class file transformer from this class loader. |
| * It will no longer be able to instrument the byte code of any classes |
| * loaded by the class loader after the invocation of this method. |
| * However, any classes already instrumented by this transformer before |
| * this method call will remain in their instrumented state. |
| * |
| * @param transformer The transformer to remove |
| */ |
| void removeTransformer(ClassFileTransformer transformer); |
| |
| /** |
| * Returns a copy of this class loader without any class file |
| * transformers. This is a tool often used by Java Persistence API |
| * providers to inspect entity classes in the absence of any |
| * instrumentation, something that can't be guaranteed within the |
| * context of a {@link ClassFileTransformer}'s |
| * {@link ClassFileTransformer#transform(ClassLoader, String, Class, |
| * java.security.ProtectionDomain, byte[]) transform} method. |
| * <p> |
| * The returned class loader's resource cache will have been cleared |
| * so that classes already instrumented will not be retained or |
| * returned. |
| * |
| * @return the transformer-free copy of this class loader. |
| */ |
| ClassLoader copyWithoutTransformers(); |
| |
| } |