Glassfish example source code file (ReflectiveClassFinder.java)

This example Glassfish source code file (ReflectiveClassFinder.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 - Glassfish tags/keywords

class, class, classloader, classnotfoundexception, enumeration, illegalaccessexception, invocationtargetexception, invocationtargetexception, io, net, network, object, object, reflection, reflectiveclassfinder, runtimeexception, runtimeexception, throwable, util

The Glassfish ReflectiveClassFinder.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2009-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package org.glassfish.osgijavaeebase;

import org.glassfish.internal.api.DelegatingClassLoader;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.Enumeration;

/**
 * An implementation of {@link org.glassfish.internal.api.DelegatingClassLoader.ClassFinder}
 * that uses reflection to call the methods of the delegate.
 * It is currently NOT used because it requires special permission
 * granted to this codebase to access protected members like findClass.
 *
 * This is pretty much an ugly hack.
 *
 * @author Sanjeeb.Sahoo@Sun.COM
 */
class ReflectiveClassFinder implements DelegatingClassLoader.ClassFinder
{
    ClassLoader delegate;
    Method findClass, findLoadedClass, findResource, findResources;

    ReflectiveClassFinder(ClassLoader delegate)
    {
        this.delegate = delegate;
        Class<ClassLoader> clazz = ClassLoader.class;
        try {
            findClass = clazz.getDeclaredMethod("findClass", String.class);
            findLoadedClass = clazz.getDeclaredMethod("findLoadedClass", String.class);
            findResource = clazz.getDeclaredMethod("findResource", String.class);
            findResources = clazz.getDeclaredMethod("findResources", String.class);
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        }
    }

    public ClassLoader getParent()
    {
        return delegate.getParent();
    }

    public Class<?> findClass(String name) throws ClassNotFoundException
    {
        try
        {
            Object result = findClass.invoke(delegate, name);
            return (Class) result;
        }
        catch (IllegalAccessException e)
        {
            throw new RuntimeException(e);
        }
        catch (InvocationTargetException e)
        {
            Throwable cause = e.getCause();
            if (cause instanceof ClassNotFoundException)
            {
                throw (ClassNotFoundException) cause;
            }
            else if (cause instanceof RuntimeException)
            {
                throw (RuntimeException) cause;
            }
            else
            {
                throw new RuntimeException(e);
            }
        }
    }

    public Class<?> findExistingClass(String name)
    {
        try
        {
            Object result = findLoadedClass.invoke(delegate, name);
            return (Class) result;
        }
        catch (IllegalAccessException e)
        {
            throw new RuntimeException(e);
        }
        catch (InvocationTargetException e)
        {
            Throwable cause = e.getCause();
            if (cause instanceof RuntimeException)
            {
                throw (RuntimeException) cause;
            }
            else
            {
                throw new RuntimeException(e);
            }
        }
    }

    public URL findResource(String name)
    {
        try
        {
            Object result = findResource.invoke(delegate, name);
            return (URL) result;
        }
        catch (IllegalAccessException e)
        {
            throw new RuntimeException(e);
        }
        catch (InvocationTargetException e)
        {
            Throwable cause = e.getCause();
            if (cause instanceof RuntimeException)
            {
                throw (RuntimeException) cause;
            }
            else
            {
                throw new RuntimeException(e);
            }
        }
    }

    public Enumeration<URL> findResources(String name) throws IOException
    {
        try
        {
            Object result = findResources.invoke(delegate, name);
            return (Enumeration<URL>) result;
        }
        catch (IllegalAccessException e)
        {
            throw new RuntimeException(e);
        }
        catch (InvocationTargetException e)
        {
            Throwable cause = e.getCause();
            if (cause instanceof RuntimeException)
            {
                throw (RuntimeException) cause;
            }
            else
            {
                throw new RuntimeException(e);
            }
        }
    }
}