/*

 * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.rmi.rmic.iiop;

import java.io.*;

import sun.tools.java.ClassPath ;

import sun.tools.java.ClassFile ;

/**

 * A ClassLoader that will ultimately use a given sun.tools.java.ClassPath to

 * find the desired file.  This works for any JAR files specified in the given

 * ClassPath as well -- reusing all of that wonderful sun.tools.java code.

 *

 *@author Everett Anderson

 */

public class ClassPathLoader extends ClassLoader

{

    private ClassPath classPath;

    public ClassPathLoader(ClassPath classPath) {

        this.classPath = classPath;

    }

    // Called by the super class

    protected Class findClass(String name) throws ClassNotFoundException

    {

        byte[] b = loadClassData(name);

        return defineClass(name, b, 0, b.length);

    }

    /**

     * Load the class with the given fully qualified name from the ClassPath.

     */

    private byte[] loadClassData(String className)

        throws ClassNotFoundException

    {

        // Build the file name and subdirectory from the

        // class name

        String filename = className.replace('.', File.separatorChar)

                          + ".class";

        // Have ClassPath find the file for us, and wrap it in a

        // ClassFile.  Note:  This is where it looks inside jar files that

        // are specified in the path.

        ClassFile classFile = classPath.getFile(filename);

        if (classFile != null) {

            // Provide the most specific reason for failure in addition

            // to ClassNotFound

            Exception reportedError = null;

            byte data[] = null;

            try {

                // ClassFile is beautiful because it shields us from

                // knowing if it's a separate file or an entry in a

                // jar file.

                DataInputStream input

                    = new DataInputStream(classFile.getInputStream());

                // Can't rely on input available() since it will be

                // something unusual if it's a jar file!  May need

                // to worry about a possible problem if someone

                // makes a jar file entry with a size greater than

                // max int.

                data = new byte[(int)classFile.length()];

                try {

                    input.readFully(data);

                } catch (IOException ex) {

                    // Something actually went wrong reading the file.  This

                    // is a real error so save it to report it.

                    data = null;

                    reportedError = ex;

                } finally {

                    // Just don't care if there's an exception on close!

                    // I hate that close can throw an IOException!

                    try { input.close(); } catch (IOException ex) {}

                }

            } catch (IOException ex) {

                // Couldn't get the input stream for the file.  This is

                // probably also a real error.

                reportedError = ex;

            }

            if (data == null)

                throw new ClassNotFoundException(className, reportedError);

            return data;

        }

        // Couldn't find the file in the class path.

        throw new ClassNotFoundException(className);

    }

}