151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski/* 251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * Copyright (c) 1999, 2006, Oracle and/or its affiliates. All rights reserved. 351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * This code is free software; you can redistribute it and/or modify it 651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * under the terms of the GNU General Public License version 2 only, as 751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * published by the Free Software Foundation. Oracle designates this 851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * particular file as subject to the "Classpath" exception as provided 951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * by Oracle in the LICENSE file that accompanied this code. 1051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 1151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * This code is distributed in the hope that it will be useful, but WITHOUT 1251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * version 2 for more details (a copy is included in the LICENSE file that 1551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * accompanied this code). 1651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 1751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * You should have received a copy of the GNU General Public License version 1851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 2 along with this work; if not, write to the Free Software Foundation, 1951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 2151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * or visit www.oracle.com if you need additional information or have any 2351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * questions. 2451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski */ 2551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski 2651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebskipackage java.lang.reflect; 2751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski 2851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski/** 2951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * {@code InvocationHandler} is the interface implemented by 3051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * the <i>invocation handler</i> of a proxy instance. 3151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 3251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * <p>Each proxy instance has an associated invocation handler. 3351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * When a method is invoked on a proxy instance, the method 3451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * invocation is encoded and dispatched to the {@code invoke} 3551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * method of its invocation handler. 3651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 3751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @author Peter Jones 3851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @see Proxy 3951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @since 1.3 4051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski */ 4151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebskipublic interface InvocationHandler { 4251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski 4351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski /** 4451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * Processes a method invocation on a proxy instance and returns 4551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * the result. This method will be invoked on an invocation handler 4651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * when a method is invoked on a proxy instance that it is 4751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * associated with. 4851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 4951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @param proxy the proxy instance that the method was invoked on 5051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 5151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @param method the {@code Method} instance corresponding to 5251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * the interface method invoked on the proxy instance. The declaring 5351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * class of the {@code Method} object will be the interface that 5451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * the method was declared in, which may be a superinterface of the 5551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * proxy interface that the proxy class inherits the method through. 5651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 5751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @param args an array of objects containing the values of the 5851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * arguments passed in the method invocation on the proxy instance, 5951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * or {@code null} if interface method takes no arguments. 6051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * Arguments of primitive types are wrapped in instances of the 6151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * appropriate primitive wrapper class, such as 6251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * {@code java.lang.Integer} or {@code java.lang.Boolean}. 6351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 6451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @return the value to return from the method invocation on the 6551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * proxy instance. If the declared return type of the interface 6651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * method is a primitive type, then the value returned by 6751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * this method must be an instance of the corresponding primitive 6851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * wrapper class; otherwise, it must be a type assignable to the 6951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * declared return type. If the value returned by this method is 7051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * {@code null} and the interface method's return type is 7151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * primitive, then a {@code NullPointerException} will be 7251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * thrown by the method invocation on the proxy instance. If the 7351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * value returned by this method is otherwise not compatible with 7451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * the interface method's declared return type as described above, 7551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * a {@code ClassCastException} will be thrown by the method 7651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * invocation on the proxy instance. 7751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 7851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @throws Throwable the exception to throw from the method 7951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * invocation on the proxy instance. The exception's type must be 8051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * assignable either to any of the exception types declared in the 8151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * {@code throws} clause of the interface method or to the 8251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * unchecked exception types {@code java.lang.RuntimeException} 8351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * or {@code java.lang.Error}. If a checked exception is 8451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * thrown by this method that is not assignable to any of the 8551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * exception types declared in the {@code throws} clause of 8651b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * the interface method, then an 8751b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * {@link UndeclaredThrowableException} containing the 8851b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * exception that was thrown by this method will be thrown by the 8951b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * method invocation on the proxy instance. 9051b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * 9151b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski * @see UndeclaredThrowableException 9251b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski */ 9351b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski public Object invoke(Object proxy, Method method, Object[] args) 9451b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski throws Throwable; 9551b1b6997fd3f980076b8081f7f1165ccc2a4008Piotr Jastrzebski} 96