org.springframework.remoting.rmi.CodebaseAwareObjectInputStream.java Source code

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Here is the source code for org.springframework.remoting.rmi.CodebaseAwareObjectInputStream.java

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/*
 * Copyright 2002-2012 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
 *
 *      https://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;
import org.springframework.lang.Nullable;

/**
 * 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.
 *
 * <p>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.)
 *
 * <p>Despite residing in the RMI package, this class is <i>not</i> 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).
 *
 * <p>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 {@code 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, @Nullable ClassLoader classLoader, String codebaseUrl)
            throws IOException {

        super(in, classLoader);
        this.codebaseUrl = 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 {@code null} to indicate RMI's default ClassLoader)
     * @param acceptProxyClasses whether to accept deserialization of proxy classes
     * (may be deactivated as a security measure)
     * @see java.io.ObjectInputStream#ObjectInputStream(java.io.InputStream)
     */
    public CodebaseAwareObjectInputStream(InputStream in, @Nullable ClassLoader classLoader,
            boolean acceptProxyClasses) throws IOException {

        super(in, classLoader, acceptProxyClasses);
        this.codebaseUrl = null;
    }

    @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);
    }

}