    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     */
    017    package org.apache.commons.io.input;
    018
    019    import java.io.IOException;
    020    import java.io.InputStream;
    021    import java.io.ObjectInputStream;
    022    import java.io.ObjectStreamClass;
    023    import java.io.StreamCorruptedException;
    024
    025    /**
    026     * A special ObjectInputStream that loads a class based on a specified
    027     * <code>ClassLoader</code> rather than the system default.
    028     * <p>
    029     * This is useful in dynamic container environments.
    030     *
    031     * @author Paul Hammant
    032     * @version $Id: ClassLoaderObjectInputStream.java 736890 2009-01-23 02:02:22Z niallp $
    033     * @since Commons IO 1.1
    034     */
    035    public 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                ClassLoader classLoader, 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(ObjectStreamClass objectStreamClass)
    066                throws IOException, ClassNotFoundException {
    067
    068            Class<?> clazz = Class.forName(objectStreamClass.getName(), false, classLoader);
    069
    070            if (clazz != null) {
    071                // the classloader knows of the class
    072                return clazz;
    073            } else {
    074                // classloader knows not of class, let the super classloader do it
    075                return super.resolveClass(objectStreamClass);
    076            }
    077        }
    078    }