/*
 * Copyright (c) 2010, 2018, 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.
 *
 * 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.
 *
 */

import java.io.File;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;

public class LE2_Loader extends ClassLoader {

    private static String classPath;
    static {
        classPath = System.getProperty("test.classes");
        if (classPath == null) {
            classPath = "";
        } else {
            classPath = classPath + File.separator;
        }
    }

    // Print routine to generate indented output that
    // reflects recursive actions of the classloader.
    int _recur = 0;
    public void print(String msg) {
        for (int i = 0; i < _recur; i++) {
            System.out.print("  ");
        }
        System.out.println(">>LE2_Loader>> " + msg);
    }

    protected Class findClass2(String name) throws ClassNotFoundException {
        print("Fetching the implementation of " + name);
        int old = _recur;
        String filename = classPath + name.replace(".", "/") + ".impl2";
        try {

            FileInputStream fi = new FileInputStream(filename);
            byte result[] = new byte[fi.available()];
            fi.read(result);

            print("call defineClass() on " + name);
            _recur++;
            // This will throw the expected LinkageError when loading the
            // second version of class B.
            Class clazz = defineClass(name, result, 0, result.length);
            _recur = old;
            print("Returning newly loaded class.");
            return clazz;
        } catch (Exception e) {
            _recur = old;
            print("Not found on disk: " + filename);
            // If we caught an exception, either the class was not found or
            // it was unreadable by our process.
            return null;
        }
    }

    protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException  {
        // Attempt a disk load first.
        Class c = findClass2(name);
        if (c == null) {
            // Check if the class has already been loaded.
            print("Checking for prior loaded class " + name);
            c = findLoadedClass(name);
            print("Letting super-loader load " + name);
            int old = _recur;
            _recur++;
            c = super.loadClass(name, false);
            _recur = old;
        }
        if (resolve) { print("Resolving class " + name); resolveClass(c); }
        print("Returning class " + c.getClassLoader() + ":" + name);
        return c;
    }
}