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The Apache Commons IO library contains utility classes, stream implementations, file filters,
file comparators, endian transformation classes, and much more.
/*
* 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;
import java.lang.reflect.Proxy;
/**
* A special ObjectInputStream that loads a class based on a specified
* {@code ClassLoader} rather than the system default.
*
* This is useful in dynamic container environments.
*
*
* @since 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(
final ClassLoader classLoader, final 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(final ObjectStreamClass objectStreamClass)
throws IOException, ClassNotFoundException {
try {
return Class.forName(objectStreamClass.getName(), false, classLoader);
} catch (final ClassNotFoundException cnfe) {
// delegate to super class loader which can resolve primitives
return super.resolveClass(objectStreamClass);
}
}
/**
* Create a proxy class that implements the specified interfaces using
* the specified ClassLoader or the super ClassLoader.
*
* @param interfaces the interfaces to implement
* @return a proxy class implementing the interfaces
* @throws IOException in case of an I/O error
* @throws ClassNotFoundException if the Class cannot be found
* @see java.io.ObjectInputStream#resolveProxyClass(java.lang.String[])
* @since 2.1
*/
@Override
protected Class resolveProxyClass(final String[] interfaces) throws IOException,
ClassNotFoundException {
final Class[] interfaceClasses = new Class[interfaces.length];
for (int i = 0; i < interfaces.length; i++) {
interfaceClasses[i] = Class.forName(interfaces[i], false, classLoader);
}
try {
return Proxy.getProxyClass(classLoader, interfaceClasses);
} catch (final IllegalArgumentException e) {
return super.resolveProxyClass(interfaces);
}
}
}