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/*

 * @test

 * @bug 6417044

 * @summary Test deadlock in MBeanRegistration.postRegister method

 * @author Eamonn McManus, Daniel Fuchs

 * @run clean PostRegisterDeadlockTest

 * @run build PostRegisterDeadlockTest

 * @run main PostRegisterDeadlockTest

 */

import java.lang.Thread.State;

import java.util.concurrent.*;

import javax.management.*;

public class PostRegisterDeadlockTest {

    public static interface BlibbyMBean {}

    public static class Blibby implements BlibbyMBean, MBeanRegistration {

        public Blibby(MBeanServer mbs, ObjectName otherName) {

            this.mbs = mbs;

            this.otherName = otherName;

        }

        public ObjectName preRegister(MBeanServer mbs, ObjectName on) {

            return on;

        }

        public void preDeregister() {}

        public void postRegister(Boolean done) {

            // If no other MBean was registered

            // do nothing.

            //

            if (otherName == null) return;

            // Check that we can unregister

            // other MBean

            try {

                Thread t = new Thread() {

                    public void run() {

                        try {

                            try {

                                mbs.unregisterMBean(otherName);

                            } catch (InstanceNotFoundException x) {

                                 // Race condition!

                                 System.out.println(otherName+

                                         " was unregistered by main thread.");

                            }

                        } catch (Throwable e) {

                            e.printStackTrace(System.out);

                            fail(e.toString());

                        }

                    }

                };

                t.start();

                t.join(5000L);

                if (t.isAlive()) {

                    if (t.getState().equals(State.BLOCKED))

                        fail("Deadlock detected");

                    else

                        fail("Test not conclusive: "+

                             "Thread is alive but not blocked.");

                }

            } catch (Throwable e) {

                e.printStackTrace(System.out);

                fail(e.toString());

            }

        }

        public void postDeregister() {}

        private final MBeanServer mbs;

        private final ObjectName otherName;

    }

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

        String previous = null;

        MBeanServer mbs = MBeanServerFactory.newMBeanServer();

        ObjectName on1 = new ObjectName("a:type=Blibby,name=\"1\"");

        ObjectName on2 = new ObjectName("a:type=Blibby,name=\"2\"");

        // Test 1:

        // 1 MBean is registered with on1

        // Another MBean is registered with on1, postRegister(FALSE) is

        // called, and the second MBean attempts to unregister first MBean in

        // postRegister:

        // postRegister starts a thread which unregisters the first MBean:

        // this must not deadlock

        //

        System.out.println("\n****  TEST #1 ****\n");

        System.out.println("Registering Blibby #1 with name: " + on1);

        mbs.registerMBean(new Blibby(mbs, null), on1);

        try {

            System.out.println("Registering Blibby #2 with same name: " + on1);

            mbs.registerMBean(new Blibby(mbs, on1), on1);

        } catch (InstanceAlreadyExistsException x) {

            System.out.println("Received expected exception: " + x);

        }

        if (mbs.isRegistered(on1)) {

            try {

                mbs.unregisterMBean(on1);

                if (failure == null)

                    fail(on1+" should have been unregistered");

            } catch (InstanceNotFoundException x) {

                // Race condition!

                System.out.println(on1+" was unregistered by mbean thread.");

            }

        }  else {

            System.out.println(on1+" was correctly unregistered.");

        }

        if (failure == previous)

            System.out.println("\n****  TEST #1 PASSED ****\n");

        previous = failure;

        // Test 2:

        // 1 MBean is registered with on1

        // Another MBean is registered with on2, postRegister(TRUE) is

        // called, and the second MBean attempts to unregister first MBean in

        // postRegister:

        // postRegister starts a thread which unregisters the first MBean:

        // this must not deadlock

        //

        System.out.println("\n****  TEST #2 ****\n");

        System.out.println("Registering Blibby #1 with name: " + on1);

        mbs.registerMBean(new Blibby(mbs, null), on1);

        System.out.println("Registering Blibby #2 with other name: " + on2);

        mbs.registerMBean(new Blibby(mbs, on1), on2);

        if (mbs.isRegistered(on1)) {

            try {

                mbs.unregisterMBean(on1);

                if (failure == null)

                    fail(on1+" should have been unregistered");

            } catch (InstanceNotFoundException x) {

                // Race condition!

                System.out.println(on1+" was unregistered by mbean thread.");

            }

        }  else {

            System.out.println(on1+" was correctly unregistered.");

        }

        System.out.println("unregistering "+on2);

        mbs.unregisterMBean(on2);

        if (failure == previous)

            System.out.println("\n****  TEST #2 PASSED ****\n");

        previous = failure;

        if (failure == null)

            System.out.println("OK: Test passed");

        else

            throw new Exception("TEST FAILED: " + failure);

    }

    private static void fail(String why) {

        System.out.println("FAILED: " + why);

        failure = (failure == null)?why:(failure+",\n"+why);

    }

    private static volatile String failure;

}