/* * Copyright 2002-2008 the original author or authors. * * Licensed 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.springframework.remoting.rmi; import java.io.IOException; import java.io.InputStream; import java.rmi.server.RMIClassLoader; import org.springframework.core.ConfigurableObjectInputStream; /** * Special ObjectInputStream subclass that falls back to a specified codebase * to load classes from if not found locally. In contrast to standard RMI * conventions for dynamic class download, it is the client that determines * the codebase URL here, rather than the "java.rmi.server.codebase" system * property on the server. * *
Uses the JDK's RMIClassLoader to load classes from the specified codebase. * The codebase can consist of multiple URLs, separated by spaces. * Note that RMIClassLoader requires a SecurityManager to be set, like when * using dynamic class download with standard RMI! (See the RMI documentation * for details.) * *
Despite residing in the RMI package, this class is not used for * RmiClientInterceptor, which uses the standard RMI infrastructure instead * and thus is only able to rely on RMI's standard dynamic class download via * "java.rmi.server.codebase". CodebaseAwareObjectInputStream is used by * HttpInvokerClientInterceptor (see the "codebaseUrl" property there). * *
Thanks to Lionel Mestre for suggesting the option and providing
* a prototype!
*
* @author Juergen Hoeller
* @since 1.1.3
* @see java.rmi.server.RMIClassLoader
* @see RemoteInvocationSerializingExporter#createObjectInputStream
* @see org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor#setCodebaseUrl
*/
public class CodebaseAwareObjectInputStream extends ConfigurableObjectInputStream {
private final String codebaseUrl;
/**
* Create a new CodebaseAwareObjectInputStream for the given InputStream and codebase.
* @param in the InputStream to read from
* @param codebaseUrl the codebase URL to load classes from if not found locally
* (can consist of multiple URLs, separated by spaces)
* @see java.io.ObjectInputStream#ObjectInputStream(java.io.InputStream)
*/
public CodebaseAwareObjectInputStream(InputStream in, String codebaseUrl) throws IOException {
this(in, null, codebaseUrl);
}
/**
* Create a new CodebaseAwareObjectInputStream for the given InputStream and codebase.
* @param in the InputStream to read from
* @param classLoader the ClassLoader to use for loading local classes
* (may be null
to indicate RMI's default ClassLoader)
* @param codebaseUrl the codebase URL to load classes from if not found locally
* (can consist of multiple URLs, separated by spaces)
* @see java.io.ObjectInputStream#ObjectInputStream(java.io.InputStream)
*/
public CodebaseAwareObjectInputStream(
InputStream in, ClassLoader classLoader, String codebaseUrl) throws IOException {
super(in, classLoader);
this.codebaseUrl = codebaseUrl;
}
@Override
protected Class resolveFallbackIfPossible(String className, ClassNotFoundException ex)
throws IOException, ClassNotFoundException {
// If codebaseUrl is set, try to load the class with the RMIClassLoader.
// Else, propagate the ClassNotFoundException.
if (this.codebaseUrl == null) {
throw ex;
}
return RMIClassLoader.loadClass(this.codebaseUrl, className);
}
@Override
protected ClassLoader getFallbackClassLoader() throws IOException {
return RMIClassLoader.getClassLoader(this.codebaseUrl);
}
}