/*

 * Copyright (c) 2003, 2010, 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.

 */

/*

 * @test

 * @bug     4593133

 * @summary Basic unit test of Thread.getStackTraces()

 * @author  Mandy Chung

 */

import java.util.*;

public class StackTraces {

    private static Object go = new Object();

    private static Object dumpObj = new Object();

    private static String[] methodNames = {"run", "A", "B", "C", "Done"};

    private static int DONE_DEPTH = 5;

    private static boolean testFailed = false;

    private static Thread one;

    private static boolean trace = false;

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

        if (args.length > 0 && args[0].equals("trace")) {

            trace = true;

        }

        one = new ThreadOne();

        one.start();

        Thread dt = new DumpThread();

        dt.setDaemon(true);

        dt.start();

        if (testFailed) {

            throw new RuntimeException("Test Failed.");

        }

    }

    static class DumpThread extends Thread {

        public void run() {

            int depth = 2;

            while (true) {

                // At each iterator, wait until ThreadOne blocks

                // to wait for thread dump.

                // Then dump stack trace and notify ThreadOne to continue.

                try {

                    sleep(2000);

                    dumpStacks(depth);

                    depth++;

                    finishDump();

                } catch (Exception e) {

                    e.printStackTrace();

                    testFailed = true;

                }

            }

        }

    }

    static class ThreadOne extends Thread {

        public void run() {

            A();

        }

        private void A() {

            waitForDump();

            B();

        }

        private void B() {

            waitForDump();

            C();

        }

        private void C() {

            waitForDump();

            Done();

        }

        private void Done() {

            waitForDump();

            // Get stack trace of current thread

            StackTraceElement[] stack = getStackTrace();

            try {

                checkStack(this, stack, DONE_DEPTH);

            } catch (Exception e) {

                e.printStackTrace();

                testFailed = true;

            }

        }

    }

    static private void waitForDump() {

        synchronized(go) {

            try {

               go.wait();

            } catch (Exception e) {

               throw new RuntimeException("Unexpected exception" + e);

            }

        }

    }

    static private void finishDump() {

        synchronized(go) {

            try {

               go.notifyAll();

            } catch (Exception e) {

               throw new RuntimeException("Unexpected exception" + e);

            }

        }

    }

    public static void dumpStacks(int depth) throws Exception {

        // Get stack trace of another thread

        StackTraceElement[] stack = one.getStackTrace();

        checkStack(one, stack, depth);

        // Get stack traces of all Threads

        Map m = Thread.getAllStackTraces();

        Set s = m.entrySet();

        Iterator iter = s.iterator();

        Map.Entry entry;

        while (iter.hasNext()) {

            entry = (Map.Entry) iter.next();

            Thread t = (Thread) entry.getKey();

            stack = (StackTraceElement[]) entry.getValue();

            if (t == null || stack == null) {

               throw new RuntimeException("Null thread or stacktrace returned");

            }

            if (t == one) {

                checkStack(t, stack, depth);

            }

        }

    }

    private static void checkStack(Thread t, StackTraceElement[] stack,

                                   int depth) throws Exception {

        if (trace) {

            printStack(t, stack);

        }

        int frame = stack.length - 1;

        for (int i = 0; i < depth && frame >= 0; i++) {

            if (! stack[frame].getMethodName().equals(methodNames[i])) {

                throw new RuntimeException("Expected " + methodNames[i] +

                                           " in frame " + frame + " but got " +

                                           stack[frame].getMethodName());

            }

            frame--;

        }

    }

    private static void printStack(Thread t, StackTraceElement[] stack) {

        System.out.println(t +

                           " stack: (length = " + stack.length + ")");

        if (t != null) {

            for (int j = 0; j < stack.length; j++) {

                System.out.println(stack[j]);

            }

            System.out.println();

        }

    }

}