Commons IO example source code file (ClassLoaderObjectInputStream.java)

This example Commons IO source code file (ClassLoaderObjectInputStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons IO tags/keywords

class, class, classloader, classloader, classloaderobjectinputstream, classloaderobjectinputstream, classnotfoundexception, inputstream, io, ioexception, ioexception, objectinputstream, override, streamcorruptedexception

The Commons IO ClassLoaderObjectInputStream.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.commons.io.input;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
import java.io.StreamCorruptedException;

/**
 * A special ObjectInputStream that loads a class based on a specified
 * <code>ClassLoader rather than the system default.
 * <p>
 * This is useful in dynamic container environments.
 *
 * @author Paul Hammant
 * @version $Id: ClassLoaderObjectInputStream.java 736890 2009-01-23 02:02:22Z niallp $
 * @since Commons IO 1.1
 */
public class ClassLoaderObjectInputStream extends ObjectInputStream {

    /** The class loader to use. */
    private final ClassLoader classLoader;

    /**
     * Constructs a new ClassLoaderObjectInputStream.
     *
     * @param classLoader  the ClassLoader from which classes should be loaded
     * @param inputStream  the InputStream to work on
     * @throws IOException in case of an I/O error
     * @throws StreamCorruptedException if the stream is corrupted
     */
    public ClassLoaderObjectInputStream(
            ClassLoader classLoader, InputStream inputStream)
            throws IOException, StreamCorruptedException {
        super(inputStream);
        this.classLoader = classLoader;
    }

    /**
     * Resolve a class specified by the descriptor using the
     * specified ClassLoader or the super ClassLoader.
     *
     * @param objectStreamClass  descriptor of the class
     * @return the Class object described by the ObjectStreamClass
     * @throws IOException in case of an I/O error
     * @throws ClassNotFoundException if the Class cannot be found
     */
    @Override
    protected Class<?> resolveClass(ObjectStreamClass objectStreamClass)
            throws IOException, ClassNotFoundException {
        
        Class<?> clazz = Class.forName(objectStreamClass.getName(), false, classLoader);

        if (clazz != null) {
            // the classloader knows of the class
            return clazz;
        } else {
            // classloader knows not of class, let the super classloader do it
            return super.resolveClass(objectStreamClass);
        }
    }
}