Glassfish example source code file (TempBundleClassLoader.java)

This example Glassfish source code file (TempBundleClassLoader.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

bufferedinputstream, bytearrayoutputstream, bytearrayoutputstream, class, classloader, classnotfoundexception, classnotfoundexception, io, ioexception, ioexception, net, network, string, tempbundleclassloader, tempbundleclassloader, unsupportedclassversionerror, url, util

The Glassfish TempBundleClassLoader.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 java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;

/**
 * This class loader only provides a new class loading namespace
 * It is useful during annotation scanning classes get loaded in that separate
 * namespace. This class loader delegates all stream handling (i.e. reading
 * actual class/resource data) operations to a delegate Bundle.
 * It only defines the Class using the byte codes.
 *
 * @author Sanjeeb.Sahoo@Sun.COM
 */
public class TempBundleClassLoader extends ClassLoader
{
    private BundleClassLoader delegate;

    public TempBundleClassLoader(BundleClassLoader delegate)
    {
        // Set our parent same as delegate's
        super(delegate.getParent());
        this.delegate = delegate;
    }

    /**
     * This method uses the delegate to use class bytes and then defines
     * the class using this class loader
     */
    protected Class findClass(String name) throws ClassNotFoundException
    {
        String entryName = name.replace('.', '/') + ".class";
        URL url = delegate.getResource(entryName);
        if (url == null)
        {
            throw new ClassNotFoundException(name);
        }
        InputStream inputStream = null;
        byte[] bytes = null;
        try
        {
            inputStream = url.openStream();
            bytes = getClassData(inputStream);
        }
        catch (IOException e)
        {
            throw new ClassNotFoundException(name, e);
        }
        finally
        {
            try
            {
                if (inputStream != null)
                {
                    inputStream.close();
                }
            }
            catch (IOException e)
            {
                // ignore
            }
        }
        // Define package information if necessary
        int lastPackageSep = name.lastIndexOf('.');
        if (lastPackageSep != -1)
        {
            String packageName = name.substring(0, lastPackageSep);
            if (getPackage(packageName) == null)
            {
                try
                {
                    // There's a small chance that one of our parents
                    // could define the same package after getPackage
                    // returns null but before we call definePackage,
                    // since the parent classloader instances
                    // are not locked.  So, just catch the exception
                    // that is thrown in that case and ignore it.
                    //
                    // It's unclear where we would get the info to
                    // set all spec and impl data for the package,
                    // so just use null.  This is consistent will the
                    // JDK code that does the same.
                    definePackage(packageName, null, null, null,
                            null, null, null, null);
                }
                catch (IllegalArgumentException iae)
                {
                    // duplicate attempt to define same package.
                    // safe to ignore.
                }
            }
        }
        Class clazz = null;
        try
        {
            clazz = defineClass(name, bytes, 0, bytes.length, null); // TODO(Sahoo): Set appropriate protection domain
            return clazz;
        }
        catch (UnsupportedClassVersionError ucve)
        {
            throw new UnsupportedClassVersionError(name + " can't be defined as we are running in Java version" +
                    System.getProperty("java.version"));
        }
    }

    public URL getResource(String name)
    {
        return delegate.getResource(name);
    }

    public Enumeration<URL> findResources(String name) throws IOException
    {
        return delegate.getResources(name);
    }

    /**
     * Returns the byte array from the given input stream.
     *
     * @param istream input stream to the class or resource
     * @throws IOException if an i/o error
     */
    private byte[] getClassData(InputStream istream) throws IOException
    {
        BufferedInputStream bstream = new BufferedInputStream(istream);
        byte[] buf = new byte[4096];
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        int num = 0;
        try
        {
            while ((num = bstream.read(buf)) != -1)
            {
                bout.write(buf, 0, num);
            }
        }
        finally
        {
            if (bstream != null)
            {
                bstream.close();
            }
        }

        return bout.toByteArray();
    }


}