    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.io.input;
    018
    019import java.io.IOException;
    020import java.io.InputStream;
    021import java.io.ObjectInputStream;
    022import java.io.ObjectStreamClass;
    023import java.io.StreamCorruptedException;
    024import java.lang.reflect.Proxy;
    025
    026/**
    027 * A special ObjectInputStream that loads a class based on a specified
    028 * {@link ClassLoader} rather than the system default.
    029 * <p>
    030 * This is useful in dynamic container environments.
    031 * </p>
    032 *
    033 * @since 1.1
    034 */
    035public class ClassLoaderObjectInputStream extends ObjectInputStream {
    036
    037    /** The class loader to use. */
    038    private final ClassLoader classLoader;
    039
    040    /**
    041     * Constructs a new ClassLoaderObjectInputStream.
    042     *
    043     * @param classLoader  the ClassLoader from which classes should be loaded
    044     * @param inputStream  the InputStream to work on
    045     * @throws IOException in case of an I/O error
    046     * @throws StreamCorruptedException if the stream is corrupted
    047     */
    048    public ClassLoaderObjectInputStream(
    049            final ClassLoader classLoader, final InputStream inputStream)
    050            throws IOException, StreamCorruptedException {
    051        super(inputStream);
    052        this.classLoader = classLoader;
    053    }
    054
    055    /**
    056     * Resolve a class specified by the descriptor using the
    057     * specified ClassLoader or the super ClassLoader.
    058     *
    059     * @param objectStreamClass  descriptor of the class
    060     * @return the Class object described by the ObjectStreamClass
    061     * @throws IOException in case of an I/O error
    062     * @throws ClassNotFoundException if the Class cannot be found
    063     */
    064    @Override
    065    protected Class<?> resolveClass(final ObjectStreamClass objectStreamClass)
    066            throws IOException, ClassNotFoundException {
    067        try {
    068            return Class.forName(objectStreamClass.getName(), false, classLoader);
    069        } catch (final ClassNotFoundException cnfe) {
    070            // delegate to super class loader which can resolve primitives
    071            return super.resolveClass(objectStreamClass);
    072        }
    073    }
    074
    075    /**
    076     * Create a proxy class that implements the specified interfaces using
    077     * the specified ClassLoader or the super ClassLoader.
    078     *
    079     * @param interfaces the interfaces to implement
    080     * @return a proxy class implementing the interfaces
    081     * @throws IOException in case of an I/O error
    082     * @throws ClassNotFoundException if the Class cannot be found
    083     * @see java.io.ObjectInputStream#resolveProxyClass(String[])
    084     * @since 2.1
    085     */
    086    @Override
    087    protected Class<?> resolveProxyClass(final String[] interfaces) throws IOException,
    088            ClassNotFoundException {
    089        final Class<?>[] interfaceClasses = new Class[interfaces.length];
    090        for (int i = 0; i < interfaces.length; i++) {
    091            interfaceClasses[i] = Class.forName(interfaces[i], false, classLoader);
    092        }
    093        try {
    094            return Proxy.getProxyClass(classLoader, interfaceClasses);
    095        } catch (final IllegalArgumentException e) {
    096            return super.resolveProxyClass(interfaces);
    097        }
    098    }
    099
    100}