/*

 * Copyright (c) 2015, 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

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 * questions.

 */

/*

 * @test

 * @bug 8140450

 * @library /lib/testlibrary

 * @build jdk.testlibrary.*

 * @summary Test if the getCallerClass method returns empty optional

 * @run main CallerFromMain exec

 */

import jdk.testlibrary.ProcessTools;

import jdk.testlibrary.OutputAnalyzer;

public class CallerFromMain {

    private static final StackWalker sw = StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);

    public static void main(String[] args) throws Exception {

        if (args.length > 0) {

            ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(true, "CallerFromMain");

            OutputAnalyzer output = ProcessTools.executeProcess(pb);

            System.out.println(output.getOutput());

            output.shouldHaveExitValue(0);

            return;

        }

        // StackWalker::getCallerClass

        // CallerFromMain::main

        // no caller

        try {

            Class<?> c = sw.getCallerClass();

            throw new RuntimeException("UOE not thrown. Caller: " + c);

        // StackWalker::getCallerClass

        // Runnable::run

        // Thread::run

        Thread t1 = new Thread(new Runnable() {

            @Override

            public void run() {

                Class<?> c = sw.getCallerClass();

                System.out.println("Call from Thread.run: " + c);

                assertThreadClassAsCaller(c);

            }

        });

        t1.setDaemon(true);

        t1.start();

        // StackWalker::getCallerClass

        // CallerFromMain::doit

        // Thread::run

        Thread t2 = new Thread(CallerFromMain::doit);

        t2.setDaemon(true);

        t2.start();

        // StackWalker::getCallerClass

        // MyRunnable::run

        // Thread::run

        Thread t3 = new Thread(new MyRunnable());

        t3.setDaemon(true);

        t3.start();

        // StackWalker::getCallerClass

        // Runnable::run

        // MyThread::run

        Thread t4 = new MyThread(new Runnable() {

            @Override

            public void run() {

                Class<?> c = sw.getCallerClass();

                System.out.println("Call from MyThread.run: " + c);

                if (c != MyThread.class) {

                    throw new RuntimeException("Expected MyThread.class but got " + c);

                }

            }

        });

        t4.setDaemon(true);

        t4.start();

        t1.join();

        t2.join();

        t3.join();

        t4.join();

    }

    static class MyThread extends Thread {

        final Runnable runnable;

        MyThread(Runnable runnable) {

            super("MyThread");

            this.runnable = runnable;

        }

        public void run() {

            runnable.run();

        }

    }

    static class MyRunnable implements Runnable {

        @Override

        public void run() {

            Class<?> c = sw.getCallerClass();

            System.out.println("Call from Thread::run: " + c);

            assertThreadClassAsCaller(c);

        }

     }

    static void doit() {

        Class<?> c = sw.getCallerClass();

        System.out.println("Call from CallerFromMain.doit: " + c);

        assertThreadClassAsCaller(c);

    }

    static void assertThreadClassAsCaller(Class<?> caller) {

        if (caller != Thread.class) {

            throw new RuntimeException("Expected Thread.class but got " + caller);

        }

    }

}