/*

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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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 */

package com.sun.xml.internal.ws.api.pipe;

import java.lang.reflect.Constructor;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.concurrent.ThreadFactory;

/**

 * Simple utility class to instantiate correct Thread instance

 * depending on Java version.

 *

 * @author miroslav.kos@oracle.com

 */

final class ThreadHelper {

    private static final String SAFE_THREAD_NAME = "sun.misc.ManagedLocalsThread";

    private static final ThreadFactory threadFactory;

    // no instantiating wanted

    private ThreadHelper() {

    }

    static {

        threadFactory = AccessController.doPrivileged(

                new PrivilegedAction<ThreadFactory> () {

                    @Override

                    public ThreadFactory run() {

                        // In order of preference

                        try {

                            try {

                                Class<Thread> cls = Thread.class;

                                Constructor<Thread> ctr = cls.getConstructor(

                                        ThreadGroup.class,

                                        Runnable.class,

                                        String.class,

                                        long.class,

                                        boolean.class);

                                return new JDK9ThreadFactory(ctr);

                            } catch (NoSuchMethodException ignored) {

                                // constructor newly added in Java SE 9

                            }

                            Class<?> cls = Class.forName(SAFE_THREAD_NAME);

                            Constructor<?> ctr = cls.getConstructor(Runnable.class);

                            return new SunMiscThreadFactory(ctr);

                        return new LegacyThreadFactory();

                    }

                }

        );

    }

    static Thread createNewThread(final Runnable r) {

        return threadFactory.newThread(r);

    }

    // A Thread factory backed by the Thread constructor that

    // suppresses inheriting of inheritable thread-locals.

    private static class JDK9ThreadFactory implements ThreadFactory {

        final Constructor<Thread> ctr;

        JDK9ThreadFactory(Constructor<Thread> ctr) { this.ctr = ctr; }

        @Override public Thread newThread(Runnable r) {

            try {

                return ctr.newInstance(null, r, "toBeReplaced", 0, false);

            } catch (ReflectiveOperationException x) {

            }

        }

    }

    // A Thread factory backed by sun.misc.ManagedLocalsThread

    private static class SunMiscThreadFactory implements ThreadFactory {

        final Constructor<?> ctr;

        SunMiscThreadFactory(Constructor<?> ctr) { this.ctr = ctr; }

            return AccessController.doPrivileged(

                    new PrivilegedAction<Thread>() {

                        @Override

                        public Thread run() {

                            try {

                                return (Thread) ctr.newInstance(r);

                            } catch (Exception e) {

                                return new Thread(r);

                            }

                        }

                    }

            );

        }

    }

    // A Thread factory backed by new Thread(Runnable)

    private static class LegacyThreadFactory implements ThreadFactory {

        @Override public Thread newThread(Runnable r) {

            return new Thread(r);

        }

    }

}