/*

 * Copyright (c) 2011, 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.lang.instrument.*;

import java.util.*;

public class RetransformBigClassAgent {

    private static int N_RETRANSFORMS = 1000;

    public static Class clz;

    public static volatile boolean doneRetransforming = false;

    // just retransform the class in a loop via a Timer

    public static void premain(String agentArgs, final Instrumentation inst) throws Exception {

        String s = agentArgs.substring(0, agentArgs.indexOf(".class"));

        clz = Class.forName(s.replace('/', '.'));

        ClassFileTransformer trans = new SimpleIdentityTransformer();

        inst.addTransformer(trans, true /* canRetransform */);

        System.gc();  // throw away anything we can before we start testing

        new Timer(true).schedule(new TimerTask() {

            public void run() {

                try {

                    int i;

                    System.out.println("Retransforming");

                    for (i = 0; i < N_RETRANSFORMS; i++) {

                        inst.retransformClasses(clz);

                        System.gc();  // throw away anything we can

                    }

                    System.out.println("Retransformed " + i + " times.");

                    RetransformBigClassAgent.doneRetransforming = true;

                }

                catch (Exception e) { e.printStackTrace(); }

            }

        }, 500);

    }

}