001/*
002 * Copyright 2002-2012 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.remoting.rmi;
018
019import java.io.IOException;
020import java.io.InputStream;
021import java.rmi.server.RMIClassLoader;
022
023import org.springframework.core.ConfigurableObjectInputStream;
024
025/**
026 * Special ObjectInputStream subclass that falls back to a specified codebase
027 * to load classes from if not found locally. In contrast to standard RMI
028 * conventions for dynamic class download, it is the client that determines
029 * the codebase URL here, rather than the "java.rmi.server.codebase" system
030 * property on the server.
031 *
032 * <p>Uses the JDK's RMIClassLoader to load classes from the specified codebase.
033 * The codebase can consist of multiple URLs, separated by spaces.
034 * Note that RMIClassLoader requires a SecurityManager to be set, like when
035 * using dynamic class download with standard RMI! (See the RMI documentation
036 * for details.)
037 *
038 * <p>Despite residing in the RMI package, this class is <i>not</i> used for
039 * RmiClientInterceptor, which uses the standard RMI infrastructure instead
040 * and thus is only able to rely on RMI's standard dynamic class download via
041 * "java.rmi.server.codebase". CodebaseAwareObjectInputStream is used by
042 * HttpInvokerClientInterceptor (see the "codebaseUrl" property there).
043 *
044 * <p>Thanks to Lionel Mestre for suggesting the option and providing
045 * a prototype!
046 *
047 * @author Juergen Hoeller
048 * @since 1.1.3
049 * @see java.rmi.server.RMIClassLoader
050 * @see RemoteInvocationSerializingExporter#createObjectInputStream
051 * @see org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor#setCodebaseUrl
052 */
053public class CodebaseAwareObjectInputStream extends ConfigurableObjectInputStream {
054
055        private final String codebaseUrl;
056
057
058        /**
059         * Create a new CodebaseAwareObjectInputStream for the given InputStream and codebase.
060         * @param in the InputStream to read from
061         * @param codebaseUrl the codebase URL to load classes from if not found locally
062         * (can consist of multiple URLs, separated by spaces)
063         * @see java.io.ObjectInputStream#ObjectInputStream(java.io.InputStream)
064         */
065        public CodebaseAwareObjectInputStream(InputStream in, String codebaseUrl) throws IOException {
066                this(in, null, codebaseUrl);
067        }
068
069        /**
070         * Create a new CodebaseAwareObjectInputStream for the given InputStream and codebase.
071         * @param in the InputStream to read from
072         * @param classLoader the ClassLoader to use for loading local classes
073         * (may be {@code null} to indicate RMI's default ClassLoader)
074         * @param codebaseUrl the codebase URL to load classes from if not found locally
075         * (can consist of multiple URLs, separated by spaces)
076         * @see java.io.ObjectInputStream#ObjectInputStream(java.io.InputStream)
077         */
078        public CodebaseAwareObjectInputStream(
079                        InputStream in, ClassLoader classLoader, String codebaseUrl) throws IOException {
080
081                super(in, classLoader);
082                this.codebaseUrl = codebaseUrl;
083        }
084
085        /**
086         * Create a new CodebaseAwareObjectInputStream for the given InputStream and codebase.
087         * @param in the InputStream to read from
088         * @param classLoader the ClassLoader to use for loading local classes
089         * (may be {@code null} to indicate RMI's default ClassLoader)
090         * @param acceptProxyClasses whether to accept deserialization of proxy classes
091         * (may be deactivated as a security measure)
092         * @see java.io.ObjectInputStream#ObjectInputStream(java.io.InputStream)
093         */
094        public CodebaseAwareObjectInputStream(
095                        InputStream in, ClassLoader classLoader, boolean acceptProxyClasses) throws IOException {
096
097                super(in, classLoader, acceptProxyClasses);
098                this.codebaseUrl = null;
099        }
100
101
102        @Override
103        protected Class<?> resolveFallbackIfPossible(String className, ClassNotFoundException ex)
104                        throws IOException, ClassNotFoundException {
105
106                // If codebaseUrl is set, try to load the class with the RMIClassLoader.
107                // Else, propagate the ClassNotFoundException.
108                if (this.codebaseUrl == null) {
109                        throw ex;
110                }
111                return RMIClassLoader.loadClass(this.codebaseUrl, className);
112        }
113
114        @Override
115        protected ClassLoader getFallbackClassLoader() throws IOException {
116                return RMIClassLoader.getClassLoader(this.codebaseUrl);
117        }
118
119}